PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 148

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX8
15.4.1.1
Once the MSSP module has been enabled, it waits for
a START condition to occur. Following the START con-
dition, the eight bits are shifted into the SSPSR register.
All incoming bits are sampled with the rising edge of the
clock (SCL) line. The value of register SSPSR<7:1> is
compared to the value of the SSPADD register. The
address is compared on the falling edge of the eighth
clock (SCL) pulse. If the addresses match, and the BF
and SSPOV bits are clear, the following events occur:
a)
b)
c)
d)
In 10-bit address mode, two address bytes need to be
received by the slave. The five Most Significant bits
(MSb) of the first address byte specify if this is a 10-bit
address. The R/W bit (SSPSTAT register) must specify
a write so the slave device will receive the second
address byte. For a 10-bit address, the first byte would
equal ‘1111 0 A9 A8 0’, where A9 and A8 are the
two MSb’s of the address.
DS30475A-page 148
The SSPSR register value is loaded into the
SSPBUF register.
The buffer full bit BF is set.
An ACK pulse is generated.
MSSP interrupt flag bit SSPIF (PIR registers) is
set on the falling edge of the ninth SCL pulse
(interrupt is generated, if enabled).
Addressing
Advanced Information
The sequence of events for 10-bit addressing is as fol-
lows, with steps 7- 9 for slave-transmitter:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Receive first (high) byte of address (the SSPIF,
BF and UA bits (SSPSTAT register) are set).
Update the SSPADD register with second (low)
byte of address (clears bit UA and releases the
SCL line).
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
Receive second (low) byte of address (bits
SSPIF, BF, and UA are set).
Update the SSPADD register with the first (high)
byte of address. If match releases SCL line, this
will clear bit UA.
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
Receive repeated START condition.
Receive first (high) byte of address (bits SSPIF
and BF are set).
Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
 2000 Microchip Technology Inc.