1
TM
March 1997
HD-6402
CMOS U n iver sal Asyn chro nous
Receiver Transmitter (UART)
Features
• 8.0MHz Operating Frequency (HD-6402B)
• 2.0MHz Operating Frequency (HD-6402R)
• Low Power CMOS Design
• Programma ble Word Length, Stop Bits and Parity
• Automatic Data Formatting and Status Generation
• Compatible with Industry Standard UARTs
• Single +5V Power Supply
• CMOS/TTL Compat ibl e Inputs
Description
The HD-6402 is a CMOS UART for interfacing computers or
microprocessors to an asynchronous serial data channel.
The receiver converts serial start, data, parity and stop bits.
The transmitter converts parallel data into serial form and
automatically adds start, parity and stop bits. The data word
length can be 5, 6, 7 or 8 bits. Parity may be odd or even.
Parity checking and generation can be inhibited. The stop
bits may be one or two or one and one-half when transmit-
ting 5-bit code.
The HD-6402 can be used in a wide range of applications
including modems, printers, peripherals and remote data
acquisition systems. Utilizing the Intersil advanced scaled
SAJI IV CMOS process permits operation clock frequencies
up to 8.0MHz (5 00K Baud). Power requi remen ts, by compar -
ison, are reduced from 300mW to 10mW. Status logic
increases flexibi lity and si m pli fies the user inter face.
Pinout HD-6402 (PDIP, CERDIP)
TOP VIEW
Ordering Information
PACKAGE TEMPERATURE RANGE 2MHz = 125K BAUD 8MHz = 500K BAUD PKG. NO.
Plastic DIP -40oC to +85oC HD3-6402R-9 HD3-6402B-9 E40.6
CERDIP -40oC to +85oC HD1-6402R-9 HD1-6402B-9 F40.6
SMD# -55oC to +125oC 5962-9052501MQA 5962-9052502MQA F40.6
13
1
2
3
4
5
6
7
8
9
10
11
12
14
15
16
17
18
19
20
VCC
NC
GND
RRD
RBR8
RBR7
RBR6
RBR5
RBR4
RBR3
RBR2
RBR1
PE
FE
OE
SFD
RRC
DRR
DR
RRI
28
40
39
38
37
36
35
34
33
32
31
30
29
27
26
25
24
23
22
21
TRC
EPE
CLS1
CLS2
SBS
PI
CRL
TBR8
TBR7
TBR6
TBR5
TBR4
TBR3
TBR2
TBR1
TRO
TRE
TBRL
TBRE
MR
Fil e Num ber 2956.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1- 888-IN TERSI L or 321- 724-71 43 |Inter sil (and design) is a trademar k of Intersi l Americas Inc .
Copyright © Intersil Americas Inc. 2001. All Rights Reserved
2
Functional Diagram
Control Definition
CONTROL WORD CHARACTER FORMAT
CLS 2 CLS 1 PI EPE SBS START BIT DATA BITS PARI TY BIT STOP BITS
00000 1 5 ODD 1
00001 1 5 ODD 1.5
0 0 0 1 0 1 5 EVEN 1
0 0 0 1 1 1 5 EVEN 1.5
001X0 1 5 NONE 1
001X1 1 5 NONE 1.5
01000 1 6 ODD 1
01001 1 6 ODD 2
0 1 0 1 0 1 6 EVEN 1
0 1 0 1 1 1 6 EVEN 2
011X0 1 6 NONE 1
0 11x 1 1 6 NONE 2
10000 1 7 ODD 1
10001 1 7 ODD 2
1 0 0 1 0 1 7 EVEN 1
1 0 0 1 1 1 7 EVEN 2
101X0 1 7 NONE 1
1 01x 1 1 7 NONE 2
11000 1 8 ODD 1
11001 1 8 ODD 2
1 1 0 1 0 1 8 EVEN 1
1 1 0 1 1 1 8 EVEN 2
111X0 1 8 NONE 1
1 11x 1 1 8 NONE 2
(24) TRE
(22) TBRE †
(23) TBRL
(40) TRC
(38) CLS1
(37) CLS2
(34) CRL
(21) MR
(17) RRC
(18) DRR
(19) DR †
(16) SFD
† OE † FE † PE
(15) (14) (13) (5) (6) (7)
† RBR8
3-STATE
BUFFERS
(8) (9) (10) (11) (12)† RBR1
RECEIVER BUFFER REGISTER
RECE I VER REG I STER
MULTIPLEXER
MULTIPLEXER
TRANSMITTER REGISTER
TRANSMITTER BUFFER REGISTER
START
STOP PARITY
LOGIC
PARITY
LOGIC
START
LOGIC
STOP
LOGIC
CONTROL
REGISTER
RECEIVER
TIMING AND
CONTROL
TRANSMITTER
TIMING AND
CONTROL
† THESE OUTPUTS ARE
THREE-STATE
(4) RRD
(20) RRI
(35) PI
(39) EPE
(16) SFD
(36) SBS
(25) TRO
(26) TBR1(27)
(30)(29)(28)
(31)
(32)
(33)TBR8
HD-6402
3
Pin Descr iption
PIN TYPE SYMBOL DESCRIPTION
1V
CC †Positive Voltage Supply
2 NC No Connec tion
3 GND Ground
4 I RRD A high l evel on REC EIVER RE GISTER DISAB LE
fo rces t he rece i v e r ho l ding ou t-pu t s RBR 1-RBR8
to high i m pedance stat e.
5 O RBR8 The contents of the RE CEI V ER BUFFER REG IS-
TER appear o n t he s e three-state ou t puts . Word f or-
mats less than 8 characters are right justified to
RBR1.
6 O RBR7 See Pin 5-RBR8
7 O RBR6 See Pin 5-RBR8
8 O RBR5 See Pin 5-RBR8
9 O RBR4 See Pin 5-RBR8
10 O RBR3 See Pin 5-RBR8
11 O RBR2 See Pin 5-RBR8
12 O RBR1 See Pin 5-RBR8
13 O PE A high level on PA RITY ERROR in dicates received
parity does n ot m atch parity p rogra mmed by c ontrol
bits. W hen parit y is i nh ibi ted thi s out put i s l ow.
14 O FE A high level on FRAMING ERROR indicates the
first stop bit was invalid.
15 O OE A high level on OVERRUN ERROR indicates the
data rec eive d flag was not cle are d befo re the las t
character was transferred to the receiver buffer
register.
16 I SFD A high leve l on STATUS FLAGS DI SABLE forc es
the outputs PE, FE, OE, DR, TBRE to a high im-
pedance state.
17 I RRC The Rece i ver regist er clock is 16X the rece iver
data rate.
18 I DRR A low level on DATA RECEIVED RESET clears
the dat a received out put DR to a lo w l evel .
19 O DR A high level on DATA RECE IVED indicates a
character has been received and transferred to
the receiver buffer register.
20 I RRI Serial data on RECEIVER REGISTER INPUT is
cl ock ed i nto the receiver regist er.
21 I MR A high level on MASTER RESET clears PE, FE,
OE and DR to a low level and sets the transmitter
register empty (TRE) to a high level 18 clock cycles
after MR falling edge. MR does not clear the receiv-
er buffer register. This input must be pulsed at least
once after power up. The HD-6402 must be master
reset after power up. The reset pulse should meet
VIH and tMR. Wait 18 cl ock cycles a fter the fal li n g
edge of MR before beginning operation.
22 O TBRE A high level on TRANSMITTER BUFFER REGIS-
TER EMPTY indicates the transmitter buffer register
has tran s ferred it s dat a t o the tran s mit ter regis ter
and is ready for new data .
23 I TBRL A low level on TRANSMIT TER BUFFER REGIS-
TER LOAD transfers data from inputs TBR1-
TBR8 into the transmitter buffer register. A low to
hig h transit i o n on T BRL initiates data transfer to
the transmitter register. If busy, transfer is auto-
matically delayed so that the two characters are
trans m i tt ed end to en d.
24 O TRE A high leve l on TRAN SMITTER REGIS TER E MP-
TY indicates completed transmission of a charac-
ter incl udi ng st op bi t s.
25 O TRO Character data, start data and stop bits appear se-
rially at the TRANSMITTER REGISTER OUTPUT.
26 I TRB1 Character data is loaded into the TRANSMITTER
BUFFER REGISTER via i n puts T BR 1-T BR 8. For
character formats less than 8 bits the TBR8, 7 and
6 in puts are ig nored corr esponding to the i r pro-
gram m ed word le ngt h.
27 I TBR2 See Pin 26-TBR1.
28 I TBR3 See Pin 26-TBR1.
29 I TBR4 See Pin 26-TBR1.
30 I TBR5 See Pin 26-TBR1.
31 I TBR6 See Pin 26-TBR1.
32 I TBR7 See Pin 26-TBR1.
33 I TBR8 See Pin 26-TBR1.
34 I CRL A high level on CONTROL REGISTER LOAD
loads the control register with the control word. The
control word is latched on the falling edge of CRL.
CRL may be tied high.
35 I PI A high level on PARITY INHIBIT inhibits parity gen-
eration, parity checking and forces PE output low.
36 I SBS A high level on STOP BIT SELECT selects 1.5
stop bits for 5 character format and 2 stop bits for
other lengths.
37 I CLS2 T hese inputs pr ogram the CH ARACTER
LENGTH SELECTED (CLS1 low CLS2 low 5 bits)
(CLS 1 hi gh CLS2 low 6 bi t s) (CLS1 lo w CLS 2
hi gh 7 bit s) (C LS1 high CLS2 hi gh 8 bits.)
38 I CLS1 See Pin 37-CLS2.
39 I EPE When PI is low, a high level on EVEN PARITY
ENAB LE gene rates and checks ev en parity . A low
level selects odd parity.
40 I TRC The TRANSMITTER REGISTER CLOCK is 16X
the transmit data rate.
†A 0. 1 µF decoupling capacitor from the VCC pin to the G ND is r ec-
ommended.
PIN TYPE SYMBOL DESCRIPTION
HD-6402
4
Transmitter Operation
The transmitter section accepts parallel data, formats the data
and transmits the data in serial form on the Transmitter Regis-
ter Output (TRO) terminal (See serial data format). Data is
loaded from the inputs TBR1-TBR8 into the Transmitter Buffer
Register by applying a logic low on the Transmitter Buffer
Register Load (TBRL) input (A). Valid data m us t be presen t at
least tset prior to and thold following the rising edge of TBRL. If
wor ds less tha n 8 bi ts ar e used , on ly the l east si gnif icant bits
are transmitted. The character is right justified, so the least
significant bit correspo nds t o TBR1 (B).
The rising edge of TBRL clears Transmitter Buffer Register
Empty (TBRE). 0 to 1 Clock cycles later, data is transferred
to the transmitter register, the Transmitter Register Empty
(TRE) pin goes to a low state, TBRE is set high and serial
data information is transmitted. The output data is clocked
by Transmitter Register Cl ock (TRC) at a clock rat e 16 ti m es
the data rate. A second low level pulse on TBRL loads data
into the Transmitter Buffer Register (C). Data transfer to the
transmitter register is delayed until transmission of the cur-
rent data is compl ete (D). Data i s automati call y trans ferre d to
the transmitter register and transmission of that character
begins one clock cycle lat er.
Receiver Operation
Data is received in serial form at the Receiver Register Input
(RRI). When no data is being received, RRI must remain
high. The data is clocked through the Receiver Register
Clock (RRC). The clock rate is 16 times the data rate. A low
level on Data Received Reset (DRR) clears the Data
Receiver (DR) line (A). During the first stop bit data is trans-
ferred from the Receiver Register to the Receiver Buffer
Register (RBR) (B). If the word is less than 8 bits, the
unused most significant bits will be a logic low. The output
character is right justified to the least significant bit RBR1. A
logic high on Overrun Error (OE) indicates overruns. An
overrun occurs when DR has not been cleared before the
present character was transferred to the RBR. One clock
cycle later DR is reset to a logic high, and Framing Error
(FE) is evaluated (C). A logic high on FE indicates an invalid
stop bit was received, a framing error. A logic high on Parity
Error (PE) indi cates a parit y error.
28
40
39
38
37
36
35
34
33
32
31
30
29
27
26
25
24
23
22
21
13
1
2
3
4
5
6
7
8
9
10
11
12
14
15
16
17
18
19
20
HD-6402
A B C D END OF LAST STOP BIT
1/2 CLOCK
0 TO 1 CLOCK
DATA
TBRL
TBRE
TRE
TRO
1
FIGURE 1. TRANSMITTER TIMING (NOT TO SCALE)
FIGURE 2. RECEIVER TIMING (NOT TO SCALE)
A B C
BEGINNING OF FIRST STOP BIT
7 1/2 CLOCK CYCLES
1 CLOCK CYCLE
RRI
RBR1-8, OE, PE
DRR
DR
FE
HD-6402
5
Star t Bit Dete ctio n
The receiver uses a 16X clock timing. The start bit could have
oc curred as muc h as o ne c lock cycl e be fore it was d etected ,
as indicat ed by the shaded port io n ( A). The center of the st a rt
bit is defined as clock count 7 1/2. If the receiver clock is a
symmetrical square wave, the center of the start bit will be
located within ±1/2 clock cycle, ±1/32 bit or 3.125% giving a
receiver margin of 46.875%. The receiver begins searching
for the next start bit at the center of the first stop bit.
Interfacing with the HD-6402
FIGURE 3. SERIAL DATA FORMAT
LSB MSB †
START BIT
PARITY † IF ENABLED
1, 11/2 OR 2 STOP BITS
5-8 DATA BITS
CLOCK
RRI INPUT START
71/2 CLOCK CYCLES
81/2 CLOCK CYCLES
COUNT 71/2 DEFINED
CENTER OF START BIT
FIGURE 4.
A
FIGURE 5. TYPICAL SERIAL DATA LINK
DIGITAL
SYSTEM
TRANSMITTER
RECEIVER
RRI
TRO
TBR1
TBR8
CONTROL
HD-6402
CONTROL
RB1
RB8
DIGITAL
SYSTEM
TRANSMITTER
RECEIVER
RRI
TRO TBR1
TBR8
CONTROL
HD-6402
CONTROL
RB1
RB8
RS232
DRIVER
RS232
RECEIVER RS232
DRIVER
RS232
RECEIVER
HD-6402
6
Absolute Maximum Ratings Thermal Information
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+8.0V
Input, Output or I/O Voltage Applied. . . . . GND -0.5V to VCC +0.5V
Storage Temperature Range . . . . . . . . . . . . . . . . . -65oC to +150oC
Junction Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +175oC
Lead Temperature (Soldering 10s). . . . . . . . . . . . . . . . . . . . +300oC
ESD Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Class 1
Typical Derating Factor . . . . . . . . . . . 1mA/MHz Increase in ICCOP
Thermal Resistance (Typical) θJA θJC
CERDIP Package . . . . . . . . . . . . . . . . 50oC/W 12oC/W
PDIP Package. . . . . . . . . . . . . . . . . . . 50oC/W N/A
Gate Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1643 Gates
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
Ope rat i ng Condi t io ns
Operating Voltage Range. . . . . . . . . . . . . . . . . . . . . +4.5V to +5.5V Operating Temperature Range
HD-6402R-9, HD6402B-9 . . . . . . . . . . . . . . . . . . .-40oC to +85oC
DC Electrical Specifications V
CC = 5.0V ± 10%, TA = -40oC to +85oC (HD-6402R-9, HD-6402B-9)
SYMBOL PARAMETER
LIMITS
UNITS CONDITIONSMIN MAX
VIH Logical ‘‘1’’ Inpu t Voltage 2.0 - V VCC = 5.5V
VIL Logical ‘‘0’’ Inpu t Voltag e - 0.8 V VCC = 4.5V
II Inp ut Le ak ag e C urr e n t -1 .0 1.0 µAV
IN = GND or VCC, VCC = 5.5V
VOH Logical ‘‘1’’ Output Voltage 3.0
VCC -0.4 -
-V IOH = -2.5mA, VCC = 4.5V
IOH = -100µA
VOL Logical ‘‘0’’ Output Voltage - 0.4 V IOL = +2.5mA, VCC = 4.5V
IOOu tpu t Le ak ag e C urr e nt -1 .0 1.0 µAV
O = GND or VCC, VCC = 5.5V
ICCSB Standby Supply Current - 100 µA VIN = GND or VCC; VCC = 5.5V,
Output Open
ICCOP Operating Supply Current (See Note) - 2.0 mA VCC = 5.5V, Clock Freq. = 2MHz,
VIN = VCC or GND, Outputs Open
NOTE: Guaranteed, but not 100% tested
Capacitance TA = +25oC
PARAMETER SYMBOL CONDITIONS
LIMIT
UNITSTYPICAL
Input Capacita nce CIN Freq. = 1MHz, all mea s ur ement s are referenced to de-
vice GN D 25 pF
Output Capacitance COUT 25 pF
AC Electrical Specifications V
CC = 5.0V ± 10%, TA = -40oC to +85oC (HD-6402R-9, HD6402B-9)
SYMBOL PARAMETER
LIMITS HD-6402R LIMITS HD-6402B
UNITS CONDITIONSMIN MAX MIN MAX
(1) fCLOCK Clock Frequency D.C. 2.0 D.C. 8.0 MHz CL = 50pF
See Swit c hing Wavef orm
(2) tPW Pulse Widths, CRL, DRR, TBRL 150 - 75 - ns
(3) tMR Pu lse Width MR 150 - 150 - ns
(4) tSET Input Data Setu p Time 50 - 20 - ns
(5) tHOLD Input Data Hold Time 60 - 20 - ns
(6) tEN Ou tp ut E na b le Time - 160 - 3 5 ns
HD-6402
7
All Intersil U.S. pro ducts are manufactured, assem bled and tested utilizing ISO9000 quality systems.
Intersil Corporati on’s quali ty ce rtificat ions can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license i s granted by i m plication or otherwise under any patent or patent rights of Intersil or its s ubsidiaries.
For informat ion regarding Intersil Corporation and its products, see www.i ntersil.com
A.C. Testing Input, Output Waveform
Test C ircui t
Switching Waveforms
FIGURE 6. DATA INPUT CYCLE FIGURE 7. CONTROL REGISTER LOAD
CYCLE FIGURE 8. STATUS FLAG OUTPUT
ENABLE TIME OR DATA OUT-
PUT ENABLE TIME
TBR1 - TBR8 VALID DATA
TBRL
(4)
tSET
(2)
tPW
(5)
tHOLD
(5)
tHOLD
(2)
tPW
(4)
tSET
VALID DATA
CLS1, CLS2, SBS, PI, EPE
CRL
(6)
tEN
SFD
RRD
STATUS OR
RBR1 - RBR8
FIGURE 9.
NOTE: A .C . Testing: All input signals must switch betw een VIL - 50% VIL and VIH + 20% VIH. Input rise and fall times are driven at 1ns/V.
INPUT
VIH + 20% VIH
VIL - 50% VIL
1.5V 1.5V
OUTPUT
VOH
VOL
FIGURE 10.
NOTE: Includes s tray and jig cap acit ance, CL = 50pF.
OUT
CL
(SEE NOTE)
HD-6402
