User guide

Redpine Signals, Inc. Proprietary and Confidential. Page 95
R
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5
5
Command
Bit Number
Description
C1
[7:6]
Command Type
“00”- Initialization Command
“01”- Read/Write Command
“10”, “11”- Reserved for future use
5
Read/Write
„0‟- Read Command
„1‟- Write Command
4
Internal/Bus Access
„0‟- SPI Slave Internal Access. Used in
register read/write
„1‟- Bus Access. Used in Master read/write
and slave read/write
3
Master/Slave Access
„0‟- Master Access. Used in master
read/write
„1‟- Slave Access. Used in slave read/write
2
2-bit or 16-bit length for the transfer
„0‟- 2-bit length for the transfer
„1‟- 16-bit length for the transfer
1:0
2-bit length (in terms of bytes) for the
transfer (valid only if bit 2 is cleared)
“00”- 4 Bytes length
“01”- 1 Byte length
“10”- 2 Bytes length
“11”- 3 Bytes length
C2
7:6
8-bit or 32-bit mode. Indicates the
granularity of the write/read data.
Note: The SPI (C1, C2, C3, C4)
commands and addresses (A1, A2, A3,
A4) will always be 8-bit irrespective of
this value.
“00”- 8-bit mode
“01”- 32-bit mode
“10”, “11”- Reserved for future use
5:0
This carries the SPI Slave‟s internal
address if bit 4 for Command C1 is