ZHCSTD7A December 2021 – November 2023 BQ79631-Q1
PRODUCTION DATA
The last procedure in the auto-addressing is to configure the COMM_CTRL[STACK_DEV] and [TOP_STACK] settings. These bits need to be configured for the broadcast read and stack read/write to work properly.
Table 8-19 shows the auto-addressing steps, assuming CONTROL1[DIR_SEL] = 0 (that is, each device will be set up to transmit command frame sent by host from its COML to COMH).
| Step | Procedure |
|---|---|
| 1 | This step is required if a device reset has occurred before performing the auto-addressing
procedure. Dummy Write to synchronize all daisy-chain devices DLL (delay-locked loop) ramp in write direction. Host sends broadcast write to write 0x00 to ECC_DATA1 to ECC_DATA8 registers. |
| 2 | Enable auto-addressing procedure. Host sends broadcast write to set CONTROL1[ADDR_WR] = 1. |
| 3 | Sending in the device addresses. Host sends broadcast write to set the consecutive addresses
to DIR0_ADDR[ADDRESS5:0]. With an example of a total of three
devices in a daisy-chain:
|
| 4 | Set up the COMM_CTRL[STACK_DEV] and [TOP_STACK] bits for each device. Option 1: Host sends single device write to each device to set the proper [STACK_DEV] and [TOP_STACK] values. Option 2 (less communication steps):
|
| 5 | This step is required if a device reset has occurred before performing the auto-addressing
procedure. Dummy read to synchronize all daisy-chain devices DLL ramp in read direction. Host sends broadcast read to read ECC_DATA1 to ECC_DATA8 registers. Host may not receive all of the data as this step synchronizes the DLL. |
| 6 | Recommended as good practice. Use broadcast read to read DIR0_ADDR registers to read back all device addresses to ensure all devices are addressed properly. |
| 7 | If the dummy write and dummy read steps are performed to synchronize the DLL, it is normal if communication fault is triggered. Clear the fault registers if that is the case. |