Document Number: 001-74494 Rev. *B Page 24 of 71
Steps to Configure CY8CMBR2110
To configure the CY8CMBR2110, follow these steps:
1. Change Device mode to LED Configuration mode.
2. Wait for 55 ms.
3. Write to all the configuration registers in the LED Configu-
ration mode.
4. Wait for 55 ms.
5. Change Device mode to Device Configuration mode.
6. Wait for 55 ms.
7. Write to all the configuration registers in the Device Configu-
ration mode.
8. Calculate checksum and enter this value in the registers.
Checksum (Checksum_MSB (0x1E) and Checksum_LSB
(0x1F) in the Device Configuration mode): Checksum is the sum
of values of the registers (0x01–0x1F) in the LED Configuration
mode and the registers (0x01–0x1D) in the Device Configuration
mode. Checksum also takes the values of any reserved register
bits. The host should not write to these bits and should add 0 for
any such bit, while calculating checksum.
Checksum_Flash_xxx registers (in the Operating mode) indicate
the checksum stored in the flash. Checksum_RAM_xxx registers
(in the Operating mode) indicate the checksum calculated by the
device and stored in the RAM.
9. Wait for 55 ms.
10.Read the Checksum matched bit in the Host_Mode register
(in the Device Configuration mode) and verify that it is set to
1. If this bit is not set, start again from the first step and recon-
figure the device. The host should keep a backup of the
configuration data if this is needed.
Checksum matched bit: The CY8CMBR2110 calculates the
checksum and compares that with the Checksum register value
entered by the host. If both the values match, the Checksum
matched bit in the Host_Mode register (in the Device Configu-
ration mode) is set to 1. If the values do not match (indicating a
possible I2C write error) this bit is cleared to 0. The host can read
the Checksum_RAM_xxx register (in the Operating mode) to
know the device calculated checksum.
11.If the Checksum matched bit is set to 1, then set the Save to
Flash bit in the Host_mode register.
Save to Flash bit: On a Save to Flash, the following sequence
is executed:
■The device copies the 64-byte data (LED Configuration mode
and Device Configuration mode) to the flash.
■A software reset is done.
■After software reset, the device is in Operating mode.
Any configuration changes are not applicable unless a Save to
Flash is done, which is useful when the device has to be
configured only once for all future operations. To ensure a
flawless Save to Flash, the device power supply must be stable,
with VDD fluctuations limited to ±5% of the VDD.
12.After a Save to Flash, wait for (TSAVE_FLASH + Device initial-
ization) time. TSAVE_FLASH is mentioned in the Flash Write
Time Specifications. The device initialization time is 350 ms
(normal Noise Immunity) or 1000 ms (high Noise Immunity).
13.Read the Factory defaults loaded bit in Device_Stat register
(in Operating mode).
Factory Defaults Loaded bit: After every reset, the device
loads the RAM with the flash content and verifies the RAM
checksum with the flash checksum to ensure there is no flash
corruption. If the checksum differs, then the device identifies it as
a flash corruption and loads the factory default value in the RAM,
and sets the Factory Defaults Loaded bit. This resets any register
value previously changed by the host. Factory default values of
each register are mentioned in the Register Map.
If the factory defaults are loaded, the I2C address of the device
also changes from the current address (set by the host) to the
default address, 37h. The host must then check for the default
I2C address on the I2C bus to communicate with the
CY8CMBR2110.
14.Setting the Factory Defaults Loaded bit corrupts the flash and
the host needs to reconfigure the device from the first step. If
this bit is clear, then the device is successfully configured.
CY8CMBR2110 Reset
You can reset the CY8CMBR2110 either through hardware or
software using the following options:
■Hardware Reset: For this option, toggle power on the
CY8CMBR2110 pins. There are two types of hardware reset:
❐Power reset – Turn OFF the external power supply on the
device VDD line and turn ON again (after power down, ensure
that the VDD is less than 100 mV, before powering backup).
On a power reset, there is a high-going pulse of 16 ms on
the HostControlGPO1 pin.
❐XRES reset – Pull the device XRES pin HIGH and then pull
LOW. On an XRES reset, there is no pulse on
HostControlGPO1 pin. In all other respects, XRES reset is
identical to power reset.
On a hardware reset, the LED Configuration mode and Device
Configuration mode register values are loaded from the flash to
the RAM. All the device blocks are initialized, System
Diagnostics is done, and an initial 5-ms pulse is sent on all the
GPOx associated with any failing CSx. This is done within
350 ms (normal Noise Immunity) or 1000 ms (high Noise
Immunity). Power-on LED Effects (if enabled) are then seen on
all the remaining GPOs. After this, the device is in the Operating
mode and normal operation begins.
■Software Reset: This is done by writing 1 to the Software Reset
bit in the Host_Mode register (in Operating mode). On a
software reset, the LED Configuration mode and Device
Configuration mode register values are loaded from the flash
to the RAM. The device auto-clears the Software Reset bit and
all the device blocks are initialized. This is done within 350 ms
(normal Noise Immunity) or 1000 ms (high Noise Immunity).
After this, the device is in the Operating mode and normal
operation begins. System Diagnostics is not done and
Power-on LED Effects do not occur. If the user has configured
the device for Power-on LED Effects and saved the settings to
flash, a hardware reset must be done to see the Power-on LED
Effects.