Philips 8-bit microcontroller with two-clock 80C51 core UM10109 Manuel D’Utilisation
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 02 — 23 May 2005
87 of 133
Philips Semiconductors
UM10109
P89LPC932A1 User manual
, SSIG (SPCTL.7) bits for the slaves are logic 0, and the slaves are selected
by the corresponding SS signals. The SPI master can use any port pin (including
P2.4/SS) to drive the SS pins.
P2.4/SS) to drive the SS pins.
12.1 Configuring the SPI
shows configuration for the master/slave modes as well as usages and directions
for the modes.
Fig 40. SPI single master multiple slaves configuration.
002aaa903
master
slave
8-BIT SHIFT
REGISTER
SPI CLOCK
GENERATOR
8-BIT SHIFT
REGISTER
MISO
MOSI
SPICLK
port
port
MISO
MOSI
SPICLK
SS
slave
8-BIT SHIFT
REGISTER
MISO
MOSI
SPICLK
SS
Table 77:
SPI master and slave selection
SPEN
SSIG
SS Pin MSTR
Master
or Slave
Mode
or Slave
Mode
MISO
MOSI
SPICLK Remarks
0
x
P2.4
x
SPI
Disabled
Disabled
P2.3
SPI disabled. P2.2, P2.3, P2.4, P2.5 are used
as port pins.
as port pins.
1
0
0
0
Slave
output
input
input
Selected as slave.
1
0
1
0
Slave
Hi-Z
input
input
Not selected. MISO is high-impedance to avoid
bus contention.
bus contention.
1
0
0
1 (-> 0)
Slave
output
input
input
P2.4/SS is configured as an input or
quasi-bidirectional pin. SSIG is 0. Selected
externally as slave if SS is selected and is
driven low. The MSTR bit will be cleared to
logic 0 when SS becomes low.
quasi-bidirectional pin. SSIG is 0. Selected
externally as slave if SS is selected and is
driven low. The MSTR bit will be cleared to
logic 0 when SS becomes low.