Datasheet

PIC16C62B/72A
DS35008C-page 42 Preliminary  1998-2013 Microchip Technology Inc.
8.3.1.1 ADDRESSING
Once the SSP module has been enabled, it waits for a
START condition to occur. Following the START condi-
tion, 8 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) The SSPSR register value is loaded into the
SSPBUF register.
b) The buffer full bit, BF is set.
c) An ACK
pulse is generated.
d) SSP interrupt flag bit, SSPIF (PIR1<3>), is set
(interrupt is generated if enabled) on the falling
edge of the ninth SCL pulse.
In 10-bit address mode, two address bytes need to be
received by the slave. The five Most Significant bits
(MSbs) of the first address byte specify if this is a 10-bit
address. Bit R/W
(SSPSTAT<2>) 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 MSbs
of the address. The sequence of events for 10-bit
address is as follows, with steps 7- 9 for slave-transmit-
ter:
1. Receive first (high) byte of Address (bits SSPIF,
BF, and bit UA (SSPSTAT<1>) are set).
2. Update the SSPADD register with second (low)
byte of Address (clears bit UA and releases the
SCL line).
3. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
4. Receive second (low) byte of Address (bits
SSPIF, BF, and UA are set).
5. Update the SSPADD register with the first (high)
byte of Address, if match releases SCL line, this
will clear bit UA.
6. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
7. Receive repeated START condition.
8. Receive first (high) byte of Address (bits SSPIF
and BF are set).
9. Read the SSPBUF register (clears bit BF) and
clear flag bit SSPIF.
TABLE 8-2 DATA TRANSFER RECEIVED BYTE ACTIONS
Status Bits as Data
Transfer is Received
SSPSR
 SSPBUF
Generate ACK
Pulse
Set bit SSPIF
(SSP Interrupt occurs
if enabled)
BF SSPOV
00 Ye s Ye s Ye s
10 No No Yes
11 No No Yes
0 1 Ye s No Ye s
Note: Shaded cells show the conditions where the user software did not properly clear the overflow condition.