Datasheet

© 2007 Microchip Technology Inc. Preliminary DS39625C-page 219
PIC18F2585/2680/4585/4680
FIGURE 17-22: I
2
C™ MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)
P
9
87
6
5
D0
D1
D2
D3D4
D5
D6D7
S
A7 A6 A5 A4
A3 A2 A1
SDA SCL
12
3
4
5
6
7
8
9
12
3
4
5
6
7
89
1234
Bus master terminates
transfer
ACK
Receiving Data from Slave
Receiving Data from Slave
D0
D1
D2
D3D4
D5
D6D7
ACK
R/W = 1
Transmit Address to Slave
SSPIF BF
ACK is not sent
Write to SSPCON2<0>
(SEN = 1),
Write to SSPBUF occurs here,
ACK from Slave
Master configured as a receiver by programming SSPCON2<3> (RCEN = 1)
PEN bit = 1 written here
Data shifted in on falling edge of CLK
Cleared in software
start XMIT
SEN = 0
SSPOV
SDA = 0, SCL = 1
while CPU
(SSPSTAT<0>)
ACK
Cleared in software
Cleared in software
Set SSPIF interrupt at end of receive
Set P bit (SSPSTAT<4>) and SSPIF
ACK from Master
Set SSPIF at end
Set SSPIF interrupt at end of Acknowledge sequence
Set SSPIF interrupt at end of Acknow- ledge sequence
of receive
Set ACKEN, start Acknowledge sequence
SDA = ACKDT = 1
RCEN cleared automatically
RCEN = 1, start next receive
Write to SSPCON2<4> to start Acknowledge sequence SDA = ACKDT (SSPCON2<5>) = 0
RCEN cleared automatically
responds to SSPIF
ACKEN
begin Start condition
Cleared in software
SDA = ACKDT = 0
Last bit is shifted into SSPSR and contents are unloaded into SSPBUF
Cleared in software
SSPOV is set because SSPBUF is still full