Philips 8-bit microcontroller with two-clock 80C51 core UM10109 사용자 설명서
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 02 — 23 May 2005
86 of 133
Philips Semiconductors
UM10109
P89LPC932A1 User manual
, SSIG (SPCTL.7) for the slave is logic 0, and SS is used to select the slave.
The SPI master can use any port pin (including P2.4/SS) to drive the SS pin.
shows a case where two devices are connected to each other and either device
can be a master or a slave. When no SPI operation is occurring, both can be configured
as masters (MSTR = 1) with SSIG cleared to 0 and P2.4 (SS) configured in
quasi-bidirectional mode. When a device initiates a transfer, it can configure P2.4 as an
output and drive it low, forcing a mode change in the other device (see
as masters (MSTR = 1) with SSIG cleared to 0 and P2.4 (SS) configured in
quasi-bidirectional mode. When a device initiates a transfer, it can configure P2.4 as an
output and drive it low, forcing a mode change in the other device (see
) to slave.
Table 76:
SPI Data register (SPDAT - address E3h) bit allocation
Bit
7
6
5
4
3
2
1
0
Symbol
MSB
LSB
Reset
0
0
0
0
0
0
0
0
Fig 38. SPI single master single slave configuration.
Fig 39. SPI dual device configuration, where either can be a master or a slave.
002aaa901
master
slave
8-BIT SHIFT
REGISTER
SPI CLOCK
GENERATOR
8-BIT SHIFT
REGISTER
MISO
MOSI
SPICLK
PORT
MISO
MOSI
SPICLK
SS
002aaa902
master
slave
8-BIT SHIFT
REGISTER
SPI CLOCK
GENERATOR
SPI CLOCK
GENERATOR
8-BIT SHIFT
REGISTER
MISO
MOSI
SPICLK
MISO
MOSI
SPICLK
SS
SS