AD7887
Rev. D | Page 19 of 24
DOUT
DIN
SCLK
CS
1ADDITIONAL PINS OMITTED FOR CLARITY.
AD78871
80511
P1.3
P1.0
P1.1
P1.2
06191-
0
26
AD7887 to MC68HC11
The serial peripheral interface (SPI) on the MC68HC11 is
configured for master mode (MSTR = 1) when the clock
polarity bit (CPOL) = 1 and the clock phase bit (CPHA) = 1.
The SPI is configured by writing to the SPI Control Register
Semiconductor, Inc., for more information. The serial transfer
takes place as two 8-bit operations. A connection diagram is
Figure 26. Interfacing to the 8051 Using Input/Output Ports
AD7887 to PIC16C6x/PIC16C7x
DOUT
DIN
SCLK
CS
1ADDITIONAL PINS OMITTED FOR CLARITY.
MC68HC111
AD78871
SCLK/PD4
MISO/PD2
MOSI/PD3
PA0
0
6191-
025
The PIC16C6x synchronous serial port (SSP) is configured as an
SPI master with the clock polarity bit = 1. This is done by writing to
the synchronous serial port control register (SSPCON). See the
PIC16/PIC17 Microcontroller User Manual.
Figure 27 shows the
hardware connections needed to interface to the PIC16C6x/
PIC16C7x. In this example, input/output port RA1 is being used to
pulse CS. This microcontroller only transfers eight bits of data
during each serial transfer operation. Therefore, two consecutive
read/write operations are needed.
Figure 25. Interfacing to the MC68HC11
AD7887 to 8051
DOUT
DIN
SCLK
CS
1ADDITIONAL PINS OMITTED FOR CLARITY.
AD78871
PIC16C6x/
PIC16C7x1
SCK/RC3
SDO/RC5
RA1
SDI/RC4
06191-
02
7
It is possible to implement a serial interface using the data ports
on the 8051. This allows a full duplex serial transfer to be imple-
mented. The technique involves bit-banging an input/output
port (for example, P1.0) to generate a serial clock and using two
other input/output ports (for example, P1.1 and P1.2) to shift
Figure 27. Interfacing to the PIC16C6x/PIC16C7x