Z8F6421PM020SC Datasheet, PDF (156/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
136
SLAS—Slave Select
If SPI enabled as a Slave,
0 = SS input pin is asserted (Low)
1 = SS input is not asserted (High).
If SPI enabled as a Master, this bit is not applicable.
SPI Mode Register
The SPI Mode register (Table 65) configures the character bit width and the direction and
value of the SS pin.
Table 65. SPI Mode Register (SPIMODE)
BITS
FIELD
7
6
Reserved
5
DIAG
RESET
R/W
R
ADDR
4
3
2
NUMBITS[2:0]
0
R/W
F63H
1
0
SSIO
SSV
Reserved—Must be 0.
DIAG - Diagnostic Mode Control bit
This bit is for SPI diagnostics. Setting this bit allows the Baud Rate Generator value to be
read using the SPIBRH and SPIBRL register locations.
0 = Reading SPIBRH, SPIBRL returns the value in the SPIBRH and SPIBRL registers
1 = Reading SPIBRH returns bits [15:8] of the SPI Baud Rate Generator; and reading SPI-
BRL returns bits [7:0] of the SPI Baud Rate Counter. The Baud Rate Counter High and
Low byte values are not buffered.
Caution:
Exercise caution if reading the values while the BRG is counting.
NUMBITS[2:0]—Number of Data Bits Per Character to Transfer
This field contains the number of bits to shift for each character transfer. Refer to the SPI
Data Register description for information on valid bit positions when the character length
is less than 8-bits.
000 = 8 bits
001 = 1 bit
010 = 2 bits
011 = 3 bits
100 = 4 bits
101 = 5 bits
PS019915-1005
Serial Peripheral Interface