Copyright © Siemens AG 2010. All rights reserved.
Page
55
ERTEC 400 Manual
Technical data subject to change
Version 1.2.2
6
SOD
Slave mode output disable
(This bit is only relevant in slave mode MS = 1)
In “Multiple slave systems," the master can send a broadcast message to all slaves in
the system in order to ensure that only one slave drives data at its Transmit output
0 = SPI can drive the SSPTXD output in slave mode
1 = SPI must not drive the SSPTXD output in slave mode
15-7
-------
Reserved
Read: Value is undefined
Write: Should always be written with zero
SSPDR
R/W
Addr.: 0x4000_2208 Default: 0x----
Description
SPI data register
Bit No.
Name
Description
15-0
DATA [15:0]
Transmit/Receive FIFO
Read = Receive FIFO
Write = Transmit FIFO
(If < 16 bits of data, the user must write the data to the Transmit FIFO in the proper
format. When data are read, they are read out correctly from the Receive FIFO.)
SSPSR
R
Addr.: 0x4000_220C Default: 0x0000
Description
SPI status register
Bit No.
Name
Description
0
TFE
Transmit FIFO empty
0 = Transmit FIFO is not empty
1 = Transmit FIFO is empty
1
TNF
Transmit FIFO not full
0 = Transmit FIFO is full
1 = Transmit FIFO is not full
2
RNE
Receive FIFO not empty
0 = Receive FIFO is empty
1 = Receive FIFO is not empty
3
RFF
Receive FIFO full
0 = Receive FIFO is not full
1 = Receive FIFO is full
4
BSY
SPI busy flag
0 = SPI is
1 = SPI is sending and/or receiving a frame or the Transmit FIFO is
not empty.
15-5
------------
Reserved
Read: Value is undefined
Write: Should always be written with zero
SSPCPSR
R/W
Addr.: 0x4000_2210 Default: 0x0000
Description
SPI clock prescale register
Bit No.
Name
Description
7 - 0
CPSDVSR
Clock prescale divisor
(Value between 2 and 254. For formula, refer to SSPCR0 Register.)
When the value is read, bit 0 is always zero.
15-5
------------
Reserved
Read: Value is undefined
Write: Should always be written with zero