*Other brands and names are the property of their respective owners.
Information in this document is provided in connection with Intel products. Intel assumes no liability whatsoever, including infringement of any patent or
copyright, for sale and use of Intel products except as provided in Intel’s Terms and Conditions of Sale for such products. Intel retains the right to make
changes to these specifications at any time, without notice. Microcomputer Products may have minor variations to this specification known as errata.
April 1996COPYRIGHT ©INTEL CORPORATION, 1996 Order Number: 272322-004
8XC51FX
CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLERS
Commercial/Express
87C51FA/83C51FA/80C51FA/87C51FB/83C51FB/87C51FC/83C51FC
*See Table 1 for Proliferation Options
YHigh Performance CHMOS
EPROM/ROM/CPU
Y12/24/33 MHz Operation
YThree 16-Bit Timer/Counters
YProgrammable Counter Array with:
Ð High Speed Output,
Ð Compare/Capture,
Ð Pulse Width Modulator,
Ð Watchdog Timer Capabilities
YUp/Down Timer/Counter
YThree Level Program Lock System
Y8K/16K/32K On-Chip Program Memory
Y256 Bytes of On-Chip Data RAM
YImproved Quick Pulse Programming
Algorithm
YBoolean Processor
Y32 Programmable I/O Lines
Y7 Interrupt Sources
YFour Level Interrupt Priority
YProgrammable Serial Channel with:
Ð Framing Error Detection
Ð Automatic Address Recognition
YTTL Compatible Logic Levels
Y64K External Program Memory Space
Y64K External Data Memory Space
YMCSÉ51 Controller Compatible
Instruction Set
YPower Saving Idle and Power Down
Modes
YONCE (On-Circuit Emulation) Mode
YExtended Temperature Range Except
for 33 MHz Offering (b40§Ctoa
85§C)
MEMORY ORGANIZATION
Device
ROM
Version
EPROM ROMLESS
Version
ROM/
Bytes
RAM
EPROM
Bytes
83C51FA 87C51FA 80C51FA 8K 256
83C51FB 87C51FB 80C51FA 16K 256
83C51FC 87C51FC 80C51FA 32K 256
These devices can address up to 64 Kbytes of external program/data memory.
The Intel 87C51FA/8XC51FB/8XC51FC is a single-chip control oriented microcontroller which is fabricated on
Intel’s reliable CHMOS III-E technology. The Intel 83C51FA/80C51FA is fabricated on CHMOS III technology.
Being a member of the MCSÉ51 controller family, the 8XC51FA/8XC51FB/8XC51FC uses the same powerful
instruction set, has the same architecture, and is pin-for-pin compatible with the existing MCS 51 controller
products. The 8XC51FA/8XC51FB/8XC51FC is an enhanced version of the 8XC52/8XC54/8XC58. Its added
features make it an even more powerful microcontroller for applications that require Pulse Width Modulation,
High Speed I/O and up/down counting capabilities such as motor control.
For the remainder of this document, the 8XC51FA, 8XC51FB, 8XC51FC will be referred to as the 8XC51FX,
unless information applies to a specific device.
8XC51FX
Table 1. Proliferation Options
Standard*1-1 -2 -24 -33
80C51FA X X X X X
83C51FA X X X X X
87C51FA X X X X X
83C51FB X X X X X
87C51FB X X X X X
83C51FC X X X X X
87C51FC X X X X X
NOTES:
*1 3.5 MHz to 12 MHz; 5V g20%
-1 3.5 MHz to 16 MHz; 5V g20%
-2 0.5 MHz to 12 MHz; 5V g20%
-24 3.5 MHz to 24 MHz; 5V g20%
-33 3.5 MHz to 33 MHz; 5V g10%
2723221
Figure 1. 8XC51FX Block Diagram
2
8XC51FX
PROCESS INFORMATION
The 87C51FA/8XC51FB/8XC51FC is manufactured
on P629.0, a CHMOS III-E process. Additional pro-
cess and reliability information is available in Intel’s
Components Quality and Reliability Handbook,
Or-
der No. 210997.
PACKAGES
Part Prefix Package Type
8XC51FX P 40-Pin Plastic DIP
D 40-Pin CERDIP
N 44-Pin PLCC
S 44-Pin QFP
2723222
DIP
27232223
PLCC
27232224
*Do not connect Reserved Pins.
QFP
Figure 2. Pin Connections
3
8XC51FX
PIN DESCRIPTIONS
VCC:Supply voltage.
VSS:Circuit ground.
VSS1:Secondary ground (not on DIP devices or any
83C51FA/80C51FA device). Provided to reduce
ground bounce and improve power supply by-pass-
ing.
NOTE:
This pin is not a substitution for the VSS pin. (Con-
nection not necessary for proper operation.)
Port 0: Port 0 is an 8-bit, open drain, bidirectional
I/O port. As an output port each pin can sink several
LS TTL inputs. Port 0 pins that have 1’s written to
them float, and in that state can be used as high-im-
pedance inputs.
Port 0 is also the multiplexed low-order address and
data bus during accesses to external Program and
Data Memory. In this application it uses strong inter-
nal pullups when emitting 1’s, and can source and
sink several LS TTL inputs.
Port 0 also receives the code bytes during EPROM
programming, and outputs the code bytes during
program verification. External pullup resistors are re-
quired during program verification.
Port 1: Port 1 is an 8-bit bidirectional I/O port with
internal pullups. The Port 1 output buffers can drive
LS TTL inputs. Port 1 pins that have 1’s written to
them are pulled high by the internal pullups, and in
that state can be used as inputs. As inputs, Port 1
pins that are externally pulled low will source current
(IIL, on the data sheet) because of the internal pull-
ups.
In addition, Port 1 serves the functions of the follow-
ing special features of the 8XC51FX:
Port Pin Alternate Function
P1.0 T2 (External Count Input to Timer/
Counter 2), Clock Out
P1.1 T2EX (Timer/Counter 2 Capture/
Reload Trigger and Direction Control)
P1.2 ECI (External Count Input to the PCA)
P1.3 CEX0 (External I/O for Compare/
Capture Module 0)
P1.4 CEX1 (External I/O for Compare/
Capture Module 1)
P1.5 CEX2 (External I/O for Compare/
Capture Module 2)
P1.6 CEX3 (External I/O for Compare/
Capture Module 3)
P1.7 CEX4 (External I/O for Compare/
Capture Module 4)
Port 1 receives the low-order address bytes during
EPROM programming and verifying.
Port 2: Port 2 is an 8-bit bidirectional I/O port with
internal pullups. The Port 2 output buffers can drive
LS TTL inputs. Port 2 pins that have 1’s written to
them are pulled high by the internal pullups, and in
that state can be used as inputs. As inputs, Port 2
pins that are externally pulled low will source current
(IIL, on the data sheet) because of the internal pull-
ups.
Port 2 emits the high-order address byte during
fetches from external Program Memory and during
accesses to external Data Memory that use 16-bit
addresses (MOVX @DPTR). In this application it
uses strong internal pullups when emitting 1’s. Dur-
ing accesses to external Data Memory that use 8-bit
addresses (MOVX @Ri), Port 2 emits the contents of
the P2 Special Function Register.
Some Port 2 pins receive the high-order address bits
during EPROM programming and program verifica-
tion.
Port 3: Port 3 is an 8-bit bidirectional I/O port with
internal pullups. The Port 3 output buffers can drive
LS TTL inputs. Port 3 pins that have 1’s written to
them are pulled high by the internal pullups, and in
that state can be used as inputs. As inputs, Port 3
pins that are externally pulled low will source current
(IIL, on the data sheet) because of the pullups.
4
8XC51FX
Port 3 also serves the functions of various special
features of the MCS-51 Family, as listed below:
Port Pin Alternate Function
P3.0 RXD (serial input port)
P3.1 TXD (serial output port)
P3.2 INT0 (external interrupt 0)
P3.3 INT1 (external interrupt 1)
P3.4 T0 (Timer 0 external input)
P3.5 T1 (Timer 1 external input)
P3.6 WR (external data memory write strobe)
P3.7 RD (external data memory read strobe)
RST: Reset input. A high on this pin for two machine
cycles while the oscillator is running resets the de-
vice. The port pins will be driven to their reset condi-
tion when a minimum VIH1 voltage is applied wheth-
er the oscillator is running or not. An internal pull-
down resistor permits a power-on reset with only a
capacitor connected to VCC.
ALE: Address Latch Enable output pulse for latching
the low byte of the address during accesses to ex-
ternal memory. This pin (ALE/PROG) is also the
program pulse input during EPROM programming for
the 87C51FX.
In normal operation ALE is emitted at a constant
rate of (/6 the oscillator frequency, and may be used
for external timing or clocking purposes. Note, how-
ever, that one ALE pulse is skipped during each ac-
cess to external Data Memory.
If desired, ALE operation can be disabled by setting
bit 0 of SFR location 8EH. With this bit set, the pin is
weakly pulled high. However, the ALE disable fea-
ture will be suspended during a MOVX or MOVC in-
struction, idle mode, power down mode and ICE
mode. The ALE disable feature will be terminated by
reset. When the ALE disable feature is suspended or
terminated, the ALE pin will no longer be pulled up
weakly. Setting the ALE-disable bit has no affect if
the microcontroller is in external execution mode.
Throughout the remainder of this data sheet, ALE
will refer to the signal coming out of the ALE/PROG
pin, and the pin will be referred to as the ALE/PROG
pin.
PSEN:Program Store Enable is the read strobe to
external Program Memory.
When the 8XC51FX is executing code from external
Program Memory, PSEN is activated twice each ma-
chine cycle, except that two PSEN activations are
skipped during each access to external Data Memo-
ry.
EA/VPP:External Access enable. EA must be
strapped to VSS in order to enable the device to
fetch code from external Program Memory locations
0000H to 0FFFH. Note, however, that if either of the
Program Lock bits are programmed, EA will be inter-
nally latched on reset.
EA should be strapped to VCC for internal program
executions.
This pin also receives the programming supply volt-
age (VPP) during EPROM programming.
XTAL1: Input to the inverting oscillator amplifier.
XTAL2: Output from the inverting oscillator amplifi-
er.
OSCILLATOR CHARACTERISTICS
XTAL1 and XTAL2 are the input and output, respec-
tively, of a inverting amplifier which can be config-
ured for use as an on-chip oscillator, as shown in
Figure 3. Either a quartz crystal or ceramic resonator
may be used. More detailed information concerning
the use of the on-chip oscillator is available in Appli-
cation Note AP-155, ‘‘Oscillators for Microcontrol-
lers.’’
To drive the device from an external clock source,
XTAL1 should be driven, while XTAL2 floats, as
shown in Figure 4. There are no requirements on the
duty cycle of the external clock signal, since the in-
put to the internal clocking circuitry is through a
divide-by-two flip-flop, but minimum and maximum
high and low times specified on the data sheet must
be observed.
An external oscillator may encounter as much as a
100 pF load at XTAL1 when it starts up. This is due
to interaction between the amplifier and its feedback
capacitance. Once the external signal meets the VIL
and VIH specifications the capacitance will not ex-
ceed 20 pF.
5
8XC51FX
2723223
C1, C2 e30 pF g10 pF for Crystals
For Ceramic Resonators, contact resonator manufacturer.
Figure 3. Oscillator Connections
2723224
Figure 4. External Clock Drive Configuration
IDLE MODE
The user’s software can invoke the Idle Mode. When
the microcontroller is in this mode, power consump-
tion is reduced. The Special Function Registers and
the onboard RAM retain their values during Idle, but
the processor stops executing instructions. Idle
Mode will be exited if the chip is reset or if an en-
abled interrupt occurs. The PCA timer/counter can
optionally be left running or paused during Idle
Mode.
POWER DOWN MODE
To save even more power, a Power Down mode can
be invoked by software. In this mode, the oscillator
is stopped and the instruction that invoked Power
Down is the last instruction executed. The on-chip
RAM and Special Function Registers retain their val-
ues until the Power Down mode is terminated.
On the 8XC51FX either hardware reset or external
interrupt can cause an exit from Power Down. Reset
redefines all the SFRs but does not change the on-
chip RAM. An external interrupt allows both the
SFRs and the on-chip RAM to retain their values.
To properly terminate Power Down the reset or ex-
ternal interrupt should not be executed before VCC is
restored to its normal operating level and must be
held active long enough for the oscillator to restart
and stabilize (normally less than 10 ms).
With an external interrupt, INT0 or INT1 must be en-
abled and configured as level-sensitive. Holding the
pin low restarts the oscillator but bringing the pin
back high completes the exit. Once the interrupt is
serviced, the next instruction to be executed after
RETI will be the one following the instruction that put
the device into Power Down.
DESIGN CONSIDERATION
#Ambient light is known to affect the internal RAM
contents during operation. If the 87C51FX appli-
cation requires the part to be run under ambient
lighting, an opaque label should be placed over
the window to exclude light.
#When the idle mode is terminated by a hardware
reset, the device normally resumes program exe-
cution, from where it left off, up to two machine
cycles before the internal reset algorithm takes
control. On-chip hardware inhibits access to inter-
nal RAM in this event, but access to the port pins
is not inhibited. To eliminate the possibility of an
unexpected write when Idle is terminated by re-
set, the instruction following the one that invokes
Idle should not be one that writes to a port pin or
to external memory.
Table 2. Status of the External Pins during Idle and Power Down
Mode Program ALE PSEN PORT0 PORT1 PORT2 PORT3
Memory
Idle Internal 1 1 Data Data Data Data
Idle External 1 1 Float Data Address Data
Power Down Internal 0 0 Data Data Data Data
Power Down External 0 0 Float Data Data Data
NOTE:
For more detailed information on the reduced power modes refer to current Embedded Microcontrollers and Processors
Handbook Volume I, and Application Note AP-252 (Embedded Applications Handbook), ‘‘Designing with the 80C51BH.’’
6
8XC51FX
ONCE MODE
The ONCE (‘‘On-Circuit Emulation’’) Mode facilitates
testing and debugging of systems using the
8XC51FX without the 8XC51FX having to be re-
moved from the circuit. The ONCE Mode is invoked
by:
1) Pull ALE low while the device is in reset and
PSEN is high;
2) Hold ALE low as RST is deactivated.
While the device is in ONCE Mode, the Port 0 pins
float, and the other port pins and ALE and PSEN are
weakly pulled high. The oscillator circuit remains ac-
tive. While the 8XC51FX is in this mode, an emulator
or test CPU can be used to drive the circuit. Normal
operation is restored when a normal reset is applied.
8XC51FX EXPRESS
The Intel EXPRESS system offers enhancements to
the operational specifications of the MCS-51 family
of microcontrollers. These EXPRESS products are
designed to meet the needs of those applications
whose operating requirements exceed commercial
standards.
The EXPRESS program includes the commercial
standard temperature range with burn-in and an ex-
tended temperature range with or without burn-in.
With the commercial standard temperature range,
operational characteristics are guaranteed over the
temperature range of 0§Cto70
§
C. With the extend-
ed temperature range option, operational character-
istics are guaranteed over the range of b40§Cto
a
85§C.
The optional burn-in is dynamic for a minimum time
of 168 hours at 125§C with VCC e6.9V g0.25V,
following guidelines in MlL-STD-883, Method 1015.
Package types and EXPRESS versions are identified
by a one- or two-letter prefix to the part number. The
prefixes are listed in Table 3.
For the extended temperature range option, this
data sheet specifies the parameters which deviate
from their commercial temperature range limits.
NOTE:
Intel offers Express Temperature specifica-
tions for all 8XC51FX speed options except
for 33 MHz.
Table 3. Prefix Identification
Prefix Package Type Temperature Range Burn-In
D Cerdip Commercial No
N PLCC Commercial No
P Plastic Commercial No
S QFP Commercial No
LD Cerdip Extended Yes
LN PLCC Extended Yes
LP Plastic Extended Yes
LS QFP Extended Yes
TD Cerdip Extended No
TN PLCC Extended No
TP Plastic Extended No
TS QFP Extended No
NOTE:
Contact distributor or local sales office to match EXPRESS prefix with proper device.
EXAMPLES:
P87C51FC indicates 87C51FC in a plastic package and specified for commercial temperature range, without burn-in.
LD87C51FC indicates 87C51FC in a cerdip package and specified for extended temperature range with burn-in.
7
8XC51FX
ABSOLUTE MAXIMUM RATINGS*
Ambient Temperature Under Bias Àb40§Ctoa
85§C
Storage Temperature ÀÀÀÀÀÀÀÀÀÀb65§Ctoa
150§C
Voltage on EA/VPP Pin to VSS ÀÀÀÀÀÀÀ0V to a13.0V
Voltage on Any Other Pin to VSS ÀÀb0.5V to a6.5V
IOL per I/O Pin ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ15 mA
Power DissipationÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ1.5W
(based on PACKAGE heat transfer limitations, not
device power consumption)
NOTICE: This data sheet contains preliminary infor-
mation on new products in production. It is valid for
the devices indicated in the revision history. The
specifications are subject to change without notice.
*
WARNING: Stressing the device beyond the ‘‘Absolute
Maximum Ratings’’ may cause permanent damage.
These are stress ratings only. Operation beyond the
‘‘Operating Conditions’’ is not recommended and ex-
tended exposure beyond the ‘‘Operating Conditions’’
may affect device reliability.
OPERATING CONDITIONS
Symbol Description Min Max Units
TAAmbient Temperature Under Bias
Commercial 0 a70 §C
Express b40 a85
VCC Supply Voltage
8XC51FX-33 4.5 5.5 V
All Others 4.0 6.0
fOSC Oscillator Frequency
8XC51FX 3.5 12
8XC51FX-1 3.5 16 MHz
8XC51FX-2 0.5 12
8XC51FX-24 3.5 24
8XC51FX-33 3.5 33
DC CHARACTERISTICS (Over Operating Conditions)
All parameter values apply to all devices unless otherwise indicated.
Symbol Parameter Min Typical Max Units Test Conditions
(Note 4)
VIL Input Low Voltage b0.5 0.2 VCC b0.1 V
VIL1 Input Low Voltage EA 0 0.2 VCC b0.3 V
VIH Input High Voltage 0.2 VCC a0.9 VCC a0.5 V
(Except XTAL1, RST)
VIH1 Input High Voltage 0.7 VCC VCC a0.5 V
(XTAL1, RST)
VOL Output Low Voltage (Note 5) 0.3 IOL e100 mA
(Ports 1, 2 and 3) 0.45 V IOL e1.6 mA (Note 1)
1.0 IOL e3.5 mA
VOL1 Output Low Voltage (Note 5) 0.3 IOL e200 mA
(Port 0, ALE/PROG, PSEN) 0.45 V IOL e3.2 mA (Note 1)
1.0 IOL e7.0 mA
VOH Output High Voltage VCC b0.3 IOH eb
10 mA
(Ports 1, 2 and 3 VCC b0.7 V IOH eb
30 mA (Note 2)
ALE/PROG and PSEN)V
CC b1.5 IOH eb
60 mA
VOH1 Output High Voltage VCC b0.3 IOH eb
200 mA
(Port 0 in External Bus Mode) VCC b0.7 V IOH eb
3.2 mA (Note 2)
VCC b1.5 IOH eb
7.0 mA
83C51FA/80C51FA (Express) IOH eb
6.0 mA
IIL Logical 0 Input Current b50 mAV
IN e0.45V
(Ports 1, 2 and 3)
8
8XC51FX
DC CHARACTERISTICS (Over Operating Conditions)
All parameter values apply to all devices unless otherwise indicated. (Continued)
Symbol Parameter Min Typical Max Units Test Conditions
(Note 4)
ILI Input leakage Current (Port 0) g10 mAV
IN eVIL or VIH
ITL Logical 1 to 0 Transition Current VIN e2V
(Ports 1, 2 and 3)
Express b750 mA
Commercial b650
RRST RST Pulldown Resistor 40 225 KX
CIO Pin Capacitance 10 pF @1MHz, 25§C
ICC Power Supply Current: (Note 3)
Active Mode
At 12 MHz (Figure 5) 15 30 mA
At 16 MHz 20 38 mA
At 24 MHz 28 56 mA
At 33 MHz 35 56 mA
Idle Mode
At 12 MHz (Figure 5) 5 7.5 mA
At 16 MHz 6 9.5 mA
At 24 MHz 7 13.5 mA
At 33 MHz 7 15 mA
Power Down Mode 5 75 mA
NOTES:
1. Capacitive loading on Ports 0 and 2 may cause noise pulses above 0.4V to be superimposed on the VOLs of ALE and
Ports 1, 2 and 3. The noise is due to external bus capacitance discharging into the Port 0 and Port 2 pins when these pins
change from 1 to 0. In applications where capacitance loading exceeds 100 pF, the noise pulses on these signals may
exceed 0.8V. It may be desirable to qualify ALE or other signals with a Schmitt Trigger, or CMOS-level input logic.
2. Capacitive loading on Ports 0 and 2 cause the VOH on ALE and PSEN to drop below the 0.9 VCC specification when the
address lines are stabilizing.
3. See Figures 69 for test conditions. Minimum VCC for power down is 2V.
4. Typicals are based on limited number of samples, and are not guaranteed. The values listed are at room temperature and 5V.
5. Under steady state (non-transient) conditions, IOL must be externally limited as follows:
Maximum IOL per port pin: 10 mA
Maximum IOL per 8-bit port -
Port 0: 26 mA
Ports 1, 2, and 3: 15 mA
Maximum total IOL for all output pins: 71 mA
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test conditions.
2723225
Note:
ICC max at 33 MHz is at 5V g10% VCC, while ICC max at 24 MHz and below is at 5V g20% VCC.
Figure 5. 8XC51FA/FB/FC ICC vs Frequency
9
8XC51FX
2723226
All other pins disconnected
TCLCH eTCHCL e5ns
Figure 6. ICC Test Condition, Active Mode
2723227
All other pins disconnected
TCLCH eTCHCL e5ns
Figure 7. ICC Test Condition Idle Mode
2723228
All other pins disconnected
Figure 8. ICC Test Condition, Power Down Mode.
VCC e2.0V to 6.0V.
27232219
Figure 9. Clock Signal Waveform for ICC Tests in Active and Idle Modes. TCLCH eTCHCL e5 ns.
10
8XC51FX
EXPLANATION OF THE AC SYMBOLS
Each timing symbol has 5 characters. The first char-
acter is always a ‘T’ (stands for time). The other
characters, depending on their positions, stand for
the name of a signal or the logical status of that
signal. The following is a list of all the characters and
what they stand for.
A: Address
C: Clock
D: Input Data
H: Logic level HIGH
I: Instruction (program memory contents)
L: Logic level LOW, or ALE
P: PSEN
Q: Output Data
R: RD signal
T: Time
V: Valid
W: WR signal
X: No longer a valid logic level
Z: Float
For example,
TAVLL eTime from Address Valid to ALE Low
TLLPL eTime from ALE Low to PSEN Low
AC CHARACTERISTICS (Over Operating Conditions, Load Capacitance for Port 0, ALE/PROG and
PSEN e100 pF, Load Capacitance for All Other Outputs e80 pF)
EXTERNAL MEMORY CHARACTERISTICS
All parameter values apply to all devices unless otherwise indicated. In this table, 8XC51FX refers to
8XC51FX, 8XC51FX-1 and 8XC51FX-2.
Symbol Parameter
Oscillator
Units
12 MHz 24 MHz 33 MHz Variable
Min Max Min Max Min Max Min Max
1/TCLCL Oscillator Frequency
MHz
8XC51FX 3.5 12
8XC51FX-1 3.5 16
8XC51FX-2 0.5 12
8XC51FX-24 3.5 24
8XC51FX-33 3.5 33
TLHLL ALE Pulse Width 127 43 21 2TCLCLb40 ns
TAVLL Address Valid to ALE Low
8XC51FX 43 TCLCLb40 ns
8XC51FX-24 12 TCLCLb30 ns
8XC51FX-33 5 TCLCLb25 ns
TLLAX Address Hold After ALE Low
8XC51FX/-24 53 12 TCLCLb30 ns
8XC51FX-33 5 TCLCLb25 ns
TLLIV ALE Low to Valid Instr In
8XC51FX 234 4TCLCLb100 ns
8XC51FX-24 91 4TCLCLb75 ns
8XC51FX-33 56 4TCLCLb65 ns
TLLPL ALE Low to PSEN Low
8XC51FX/-24 53 12 TCLCLb30 ns
8XC51FX-33 5 TCLCLb25 ns
TPLPH PSEN Pulse Width 205 80 46 3TCLCLb45
TPLIV PSEN Low to Valid Instr In
8XC51FX 145 3TCLCLb105 ns
8XC51FX-24 35 3TCLCLb90 ns
8XC51FX-33 35 3TCLCLb55 ns
TPXIX Input Instr Hold after PSEN 000 0 ns
11
8XC51FX
EXTERNAL MEMORY CHARACTERISTICS (Continued)
All parameter values apply to all devices unless otherwise indicated
Symbol Parameter
Oscillator
Units
12 MHz 24 MHz 33 MHz Variable
Min Max Min Max Min Max Min Max
TPXIZ Input Instr Float After PSEN
8XC51FX 59 TCLCL-25 ns
8XC51FX-24 21 TCLCL-20 ns
8XC51FX-33 5 TCLCL-25 ns
TAVIV Address to Valid Instr In
8XC51FX/-24 312 103 5TCLCLb105 ns
8XC51FX-33 71 5TCLCLb80 ns
TPLAZ PSEN Low to Address Float 10 10 10 10 ns
TRLRH RD Pulse Width 400 150 82 6TCLCLb100 ns
TWLWH WR Pulse Width 400 150 82 6TCLCLb100 ns
TRLDV RD Low to Valid Data In
8XC51FX 252 5TCLCLb165 ns
8XC51FX-24 113 5TCLCLb95 ns
8XC51FX-33 61 5TCLCLb90 ns
TRHDX Data Hold After RD 000 0 ns
TRHDZ Data Float After RD
8XC51FX/24 107 23 2TCLCLb60 ns
8XC51FX-33 35 2TCLCLb25 ns
TLLDV ALE Low to Valid Data In
8XC51FX 517 8TCLCLb150 ns
8XC51FX-24/33 243 150 8TCLCLb90 ns
TAVDV Address to Valid Data In
8XC51FX 585 9TCLCLb165 ns
8XC51FX-24/33 285 180 9TCLCLb90 ns
TLLWL ALE Low to RD or WR Low 200 300 75 175 41 140 3TCLCLb50 3TCLCLa50 ns
TAVWL Address to RD or WR Low
8XC51FX 203 4TCLCLb130 ns
8XC51FX-24 77 4TCLCLb90 ns
8XC51FX-33 46 4TCLCLb75 ns
TQVWX Data Valid to WR Transition
8XC51FX 33 TCLCLb50 ns
8XC51FX-24/33 12 0 TCLCLb30 ns
TWHQX Data Hold After WR
8XC51FX 33 TCLCLb50 ns
8XC51FX-24 7 TCLCLb35 ns
8XC51FX-33 3 TCLCLb27 ns
TQVWH Data Valid to WR High
8XC51FX 433 7TCLCLb150 ns
8XC51FX-24/33 222 142 7TCLCLb70 ns
TRLAZ RD Low to Address Float 0 0 0 0 ns
TWHLH RD or WR High to ALE High
8XC51FX 43 123 TCLCLb40 TCLCLa40 ns
8XC51FX-24 12 71 TCLCLb30 TCLCLa30 ns
8XC51FX-33 5 55 TCLCLb25 TCLCLa25 ns
12
8XC51FX
EXTERNAL PROGRAM MEMORY READ CYCLE
2723229
EXTERNAL DATA MEMORY READ CYCLE
27232210
EXTERNAL DATA MEMORY WRITE CYCLE
27232211
13
8XC51FX
SERIAL PORT TIMINGÐSHIFT REGISTER MODE
Test Conditions: Over Operating Conditions; Load Capacitance e80 pF
Symbol Parameter
Oscillator
Units
12 MHz 24 MHz 33 MHz Variable
Min Max Min Max Min Max Min Max
TXLXL Serial Port 1 0.50 0.36 12TCLCL ms
Clock
Cycle Time
TQVXH Output Data 700 284 167 10TCLCLb133 ns
Setup to Clock
Rising Edge
TXHQX Output Data
Hold After Clock
Rising Edge
8XC51FX 50 2TCLCLb117 ns
8XC51FX-24/33 34 10 2TCLCLb50 ns
TXHDX Input Data Hold 0 0 0 0 ns
After Clock
Rising Edge
TXHDV Clock Rising 700 283 167 10TCLCLb133 ns
Edge to Input
Data Valid
SHIFT REGISTER MODE TIMING WAVEFORMS
27232212
14
8XC51FX
EXTERNAL CLOCK DRIVE
Symbol Parameter Min Max Units
1/TCLCL Oscillator Frequency MHz
8XC51FX 3.5 12 MHz
8XC51FX-1 3.5 16 MHz
8XC51FX-2 0.5 12 MHz
8XC51FX-24 3.5 24 MHz
8XC51FX-33 3.5 33 MHz
TCHCX High Time 20 ns
8XC51FX-24/33 0.35 TOSC 0.65 TOSC ns
TCLCX Low Time 20 ns
8XC51FX-24/33 0.35 TOSC 0.65 TOSC ns
TCLCH Rise Time 20 ns
8XC51FX-24 10 ns
8XC51FX-33 5 ns
TCHCL Fall Time 20 ns
8XC51FX-24 10 ns
8XC51FX-33 5 ns
EXTERNAL CLOCK DRIVE WAVEFORM
27232213
AC TESTING INPUT, OUTPUT WAVEFORMS
27232214
AC Inputs during testing are driven at VCCb0.5V for a Logic ‘‘1’’
and 0.45V for a Logic ‘‘0’’. Timing measurements are made at VIH
min for a Logic ‘‘1’’ and VOL max for a Logic ‘‘0’’.
FLOAT WAVEFORMS
27232215
For timing purposes a port pin is no longer floating when a
100 mV change from load voltage occurs, and begins to float
when a 100 mV change from the loaded VOH/VOL level occurs.
IOL/IOH eg20 mA.
15
8XC51FX
PROGRAMMING THE EPROM/OTP
To be programmed, the part must be running with a
4 to 6 MHz oscillator. (The reason the oscillator
needs to be running is that the internal bus is being
used to transfer address and program data to appro-
priate internal EPROM locations.) The address of an
EPROM location to be programmed is applied to
Port 1 and pins P2.0 - P2.4 of Port 2, while the code
byte to be programmed into that location is applied
to Port 0. The other Port 2 and 3 pins, RST PSEN,
and EA/VPP should be held at the ‘‘Program’’ levels
indicated in Table 4. ALE/PROG is pulsed low to
program the code byte into the addressed EPROM
location. The setup is shown in Figure 10.
Normally EA/VPP is held at logic high until just be-
fore ALE/PROG is to be pulsed. Then EA/VPP is
raised to VPP, ALE/PROG is pulsed low, and then
EA/VPP is returned to a valid high voltage. The volt-
age on the EA/VPP pin must be at the valid EA/VPP
high level before a verify is attempted. Waveforms
and detailed timing specifications are shown in later
sections of this data sheet.
NOTE:
#EA/VPP pin must not be allowed to go above the
maximum specified VPP level for any amount of
time. Even a narrow glitch above that voltage lev-
el can cause permanent damage to the device.
The VPP source should be well regulated and free
of glitches.
Table 4. EPROM Programming Modes
Mode RST PSEN ALE/ EA/ P2.6 P2.7 P3.3 P3.6 P3.7
PROG VPP
Program Code Data H L ß12.75V L H H H H
Verify Code Data H L H H L L L H H
Program Encryption H L ß12.75V L H H L H
Array Address 0 3FH
Program Lock Bit 1 H L ß12.75V H H H H H
Bits Bit 2 H L ß12.75V H H H L L
Bit 3 H L ß12.75V H L H H L
Read Signature Byte H L H H L L L L L
27232220
*See Table 4 for proper input on these pins
Figure 10. Programming the EPROM
16
8XC51FX
PROGRAMMING ALGORITHM
Refer to Table 4 and Figures 10 and 11 for address,
data, and control signals set up. To program the
87C51FX the following sequence must be exercised.
1. Input the valid address on the address lines.
2. Input the appropriate data byte on the data
lines.
3. Activate the correct combination of control sig-
nals.
4. Raise EA/VPP from VCC to 12.75V g0.25V.
5. Pulse, ALE/PROG 5 times for the EPROM ar-
ray, and 25 times for the encryption table and
the lock bits.
Repeat 1 through 5 changing the address and data
for the entire array or until the end of the object file is
reached.
PROGRAM VERIFY
Program verify may be done after each byte or block
of bytes is programmed. In either case a complete
verify of the programmed array will ensure reliable
programming of the 87C51FX.
The lock bits cannot be directly verified. Verification
of the lock bits is done by observing that their fea-
tures are enabled.
27232221
Figure 11. Programming Signals Waveforms
ROM and EPROM Lock System
The 87C51FX program lock system, when pro-
grammed, protects the onboard program against
software piracy.
The 83C51FX has a one-level program lock system
and a 64-byte encryption table. See line 2 of Table
5. If program protection is desired, the user submits
the encryption table with their code, and both the
lock-bit and encryption array are programmed by the
factory. The encryption array is not available without
the lock bit. For the lock bit to be programmed, the
user must submit an encryption table. The 83C51FA
does not have protection features.
The 87C51FX has a 3-level program lock system
and a 64-byte encryption array. Since this is an
EPROM device, all locations are user-programma-
ble. See Table 5.
Table 5. Program Lock Bits and the Features
Program Lock Bits ProtectIon Type
LB1 LB2 LB3
1 U U U No Program Lock features enabled. (Code verify will still be encrypted by the
Encryption Array if programmed.)
2 P U U MOVC instructions executed from external program memory are disabled from
fetching code bytes from internal memory, EA is sampled and latched on Reset, and
further programming of the EPROM is disabled.
3 P P U Same as 2, also verify is disabled.
4 P P P Same as 3, also external execution is disabled.
Any other combination of the lock bits is not defined.
17
8XC51FX
Encryption Array
Within the EPROM array are 64 bytes of Encryption
Array that are initially unprogrammed (all 1’s). Every
time that a byte is addressed during a verify, 6 ad-
dress lines are used to select a byte of the Encryp-
tion Array. This byte is then exclusive-NOR’ed
(XNOR) with the code byte, creating an Encryption
Verify byte. The algorithm, with the array in the un-
programmed state (all 1’s), will return the code in its
original, unmodified form. For programming the En-
cryption Array, refer to Table 4 (Programming the
EPROM).
When using the encryption array, one important fac-
tor needs to be considered. If a code byte has the
value 0FFH, verifying the byte will produce the en-
cryption byte value. lf a large block (l64 bytes) of
code is left unprogrammed, a verification routine will
display the contents of the encryption array. For this
reason all unused code bytes should be pro-
grammed with some value other than 0FFH, and not
all of them the same value. This will ensure maxi-
mum program protection.
Program Lock Bits
The 87C51FX has 3 programmable lock bits that
when programmed according to Table 5 will provide
different levels of protection for the on-chip code
and data.
Erasing the EPROM also erases the encryption ar-
ray and the program lock bits, returning the part to
full functionality.
Reading the Signature Bytes
The 87C51FX has 3 signature bytes in locations
30H, 31H, and 60H. The 83C51FA has 2 signature
bytes in locations 30H and 31H. To read these bytes
follow the procedure for EPROM verify, but activate
the control lines provided in Table 4 for Read Signa-
ture Byte.
Location Device Contents
30H All 89H
31H All 58H
60H 83C51FA 7AH/FAH
87C51FA FAH
83C51FB 7BH/FBH
87C51FB FBH
83C51FC 7CH/FCH
87C51FC FCH
Erasure Characteristics (Windowed
Packages Only)
Erasure of the EPROM begins to occur when the
chip is exposed to light with wavelength shorter than
approximately 4,000 Angstroms. Since sunlight and
fluorescent lighting have wavelengths in this range,
exposure to these light sources over an extended
time (about 1 week in sunlight, or 3 years in room-
level fluorescent lighting) could cause inadvertent
erasure. If an application subjects the device to this
type of exposure, it is suggested that an opaque la-
bel be placed over the window.
The recommended erasure procedure is exposure
to ultraviolet light (at 2537 Angstroms) to an integrat-
ed dose of at least 15 W-sec/cm. Exposing the
EPROM to an ultraviolet lamp of 12,000 mW/cm rat-
ing for 30 minutes, at a distance of about 1 inch,
should be sufficient.
Erasure leaves all the EPROM Cells in a 1’s state.
18
8XC51FX
EPROM PROGRAMMING AND VERIFICATION CHARACTERISTICS
(TAe21§Cto27
§
C; VCC e5V g20%; VSS e0V)
Symbol Parameter Min Max Units
VPP Programming Supply Voltage 12.5 13.0 V
IPP Programming Supply Current 75 mA
1/TCLCL Oscillator Frequency 4 6 MHz
TAVGL Address Setup to PROG Low 48TCLCL
TGHAX Address Hold after PROG 48TCLCL
TDVGL Data Setup to PROG Low 48TCLCL
TGHDX Data Hold after PROG 48TCLCL
TEHSH P2.7 (ENABLE) High to VPP 48TCLCL
TSHGL VPP Setup to PROG Low 10 ms
TGHSL VPP Hold after PROG 10 ms
TGLGH PROG Width 90 110 ms
TAVQV Address to Data Valid 48TCLCL
TELQV ENABLE Low to Data Valid 48TCLCL
TEHQZ Data Float after ENABLE 0 48TCLCL
TGHGL PROG High to PROG Low 10 ms
EPROM PROGRAMMING AND VERIFICATION WAVEFORMS
27232218
NOTE:
*5 pulses for the EPROM array, 25 pulses for the encryption table and lock bits.
19
8XC51FX
Thermal Impedance
All thermal impedance data is approximate for static
air conditions at 1W of power dissipation. Values will
change depending on operating conditions and ap-
plications. See the Intel Packaging Handbook (Order
No. 240800) for a description of Intel’s thermal im-
pedance test methodology.
Package iJA iJC Device
P45
§
C/W 16§C/W All
D36
§
C/W 13§C/W 80C51FA, 83C51FA,
8XC51FC
45§C/W 15§C/W 87C51FA, 8XC51FB
N46
§
C/W 16§C/W All
S97
§
C/W 24§C/W FA
96§C/W 24§C/W FB
87§C/W 18§C/W FC
DATA SHEET REVISION HISTORY
Data sheets are changed as new device information becomes available. Verify with your local Intel sales office
that you have the latest version before finalizing a design or ordering devices.
The following differences exist between this datasheet (272322-003) and the previous version (272322-002):
1. Removed 8XC51FX-3 and 8XC51FX-20, replaced with 8XC51FX-24.
2. Included 8XC51FX-24 and 8XC51FX-33 devices.
3. 80C51FA and 83C51FA now have the same features as 87C51FA, 8XC51FB and 8XC51FC; same DC spec
used for all devices.
The following differences exist between the ‘‘-002’’ and ‘‘-001’’ version of 8XC51FX datasheet:
1. Removed 8XC51FX-L from datasheet.
2. Include VOH1 for 83C51FA (Express)/80C51FA (Express).
This 8XC51FX datasheet (272322-001) replaces the following datasheets:
87C51FA/83C51FA/80C51FA 270258-007
83C51FA/80C51FA EXPRESS 270620-001
87C51FA EXPRESS 270619-001
87C51FA-20/-3 272081-002
87C51FB/83C51FB 270563-005
87C51FB-20/-3 83C51FB-20/-3 272080-002
87C51FB/83C51FB EXPRESS 270767-002
87C51FC/83C51FC 270789-004
87C51FC/83C51FC EXPRESS 270903-001
87C51FC-20/-3 83C51FC-20/-3 272028-002
20