GS6151 Datasheet, PDF (38/77 Pages) Semtech Corporation – Multi-Rate 6G UHD-SDI

2. Write to Unit Address 0 selecting HOST_CONFIG (ADDRESS = 0), with the
GSPI_LINK_DISABLE bit set to 0 and the DEVICE_UNIT_ADDRESS field set to a
unique Unit Address. This configures DEVICE_UNIT_ADDRESS for the first device in
the chain. Each subsequent such write to Unit Address 0 will configure the next
device in the chain. If there are 32 devices in a chain, the last (32nd) device in the
chain must use DEVICE_UNIT_ADDRESS value 0.
3. Repeat step 2 using new, unique values for the DEVICE_UNIT_ADDRESS field in
HOST_CONFIG until all devices in the chain have been configured with their own
unique Unit Address value.
Note: t_{cmd_GSPI_conf} delay must be observed after every write that modifies
HOST_CONFIG.
All connected devices receive this command (by default the Unit Address of all devices
is 0), and the Loop-Through operation will be re-established for all connected devices.
Once configured, each device will only respond to Command Words with a
UNIT ADDRESS field matching the DEVICE_UNIT_ADDRESS in HOST_CONFIG
Note: Although the Loop-Through and Bus-Through configurations are compatible
with previous generation GSPI enabled devices (backward compatibility), only devices
supporting Unit Addressing can share a chip select. All devices on any single chip select
must be connected in a contiguous chain with only the last device's SDOUT connected
to the application host processor. Multiple chains configured in Bus-Through mode can
have their final SDOUT outputs connected to a single application host processor input.
4.11.10 Default GSPI Operation
By default at power up or after a device reset, the GS6151 is set for Loop-Through
Operation and the internal DEVICE_UNIT_ADDRESS field of the device is set to 0.
Figure 4-21 shows a functional block diagram of the Configuration and Status Register
(CSR) map in the GS6151 for non-extended memory accesses (EMEM = 0).
At power-up or after a device reset, DEVICE_UNIT_ADDRESS = 00h
bits
CMD
[15] [14]
[13] [12]
R/W
BCAST
ALL
EMEM
Auto
Inc
[11:7]
Unit Address
32 devices
bits
DATA
[15:0]
Data to be written / Read Data
[6:0]
Local Address
128 registers
Compare
bits
Reg 0
[15]
[14]
RESERVED
GSPI_LINK
_DISABLE
[13]
GSPI_BUS_
THROUGH
_ENABLE
[12:5]
RESERVED
[4:0]
DEVICE_UNIT_ADDRESS
Read/Write
Reg 1
Reg 128
Configuration and Status Registers
Figure 4-21: Internal Register Map Functional Block Diagram
GS6151
Final Data Sheet
PDS-060389
Rev.4
August 2015
www.semtech.com
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