4.7.2
SPI Register Description
SSPCR0
R/W
Addr.: 0x4000_2200 Default: 0x0000
Description
Control register 0. Configuration frame format and baud rate for SPI.
Bit No.
Name
Description
3 - 0
DSS
Data Size Select
0000 Reserved (undefined) 1000 9-Bit Data
0001 Reserved (undefined) 1001 10-Bit Data
0010 Reserved (undefined) 1010 11-Bit Data
0011 4-Bit Data 1011 12-Bit Data
0100 5-Bit Data 1100 13-Bit Data
0101 6-Bit Data 1101 14-Bit Data
0110 7-Bit Data 1110 15-Bit Data
0111 8-Bit Data 1111 16-Bit Data
5 - 4
FRF
Frame Format
00
Motorola SPI frame format
01
TI synchronous serial frame format
02
National Microwire frame format
03
Reserved (undefined operation)
6 SPO
Serial Clock Output
Polarity
Can only be used in Motorola SPI frame format.
0 Received bits are engaged on the rising edge of SCLKIN/OUT.
Sent bits are switched on the falling edge of SCLKIN/OUT.
1 Received bits are engaged on the falling edge of SCLKIN/OUT.
Sent bits are switched on the rising edge of SCLKIN/OUT.
7 SPH
Phase of
Transmission Bit
Can only be used in Motorola SPI frame format.
0 Received MSB is expected after frame signal has gone to Low
1 Received MSB is expected ½ clock cycle after frame signal has gone to Low
15-8 SCR
Serial Clock Rate
The serial clock rate is taken for calculation of the Transmit/Receive bit rate.
The calculation formula is as follows:
F
SSPCLK
----------------------------------------
CPSDVSR x (1 + SCR)
SCR := 1 to 255
CPSDVSR := 2 to 254 (for a description, refer to SSPCPSR Register)
SSPCR1
R/W
Addr.: 0x4000_2204 Default: 0x0000
Description
Control register 1. Configuration frame format and baud rate for SPI.
Bit No.
Name
Description
0 RIE
Receive FIFO interrupt enable:
0 = Receive FIFO half full or more interrupt
SSPRXINTR
is disabled
1 = Receive FIFO half full or more interrupt
SSPRXINTR
is enabled
1 TIE
Transmit FIFO interrupt enable:
0 = Transmit FIFO half full or less interrupt
SSPTXINTR
is disabled
1 = Transmit FIFO half full or less interrupt
SSPTXINTR
is enabled
2 RORIE
Receive FIFO overrun interrupt enable:
0 = FIFO overrun display interrupt
SSPRORINTR
is disabled
(When this bit is deleted, the
SSPRORINTR
interrupt is also deleted if this interrupt
was currently being enabled)
1 = FIFO overrun display interrupt
SSPRORINTR
is enabled
3
LBM
Loop back mode
0 = Normal serial operation is active
1 = Loop back mode is active. (The output of the Transmit serial shifter is connected
internally to the input of the Receive serial shifter.)
4 SSE
Synchronous
serial port enable:
0 = SPI port is disabled
1 = SPI port is enabled
5 MS
Master/slave
mode
select
(This bit can only be changed if Bit 4 SSE = 0)
0 = Device is master (default)
1 = Device is slave
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
Copyright © Siemens AG 2007. All rights reserved.
56
ERTEC 200 Manual
Technical data subject to change
Version 1.1.0