PIC18F24 MICROCHIP [Microchip Technology], PIC18F24 Datasheet - Page 169

• Manufacturer Part Number: PIC18F24
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

17.4.6
Master mode is enabled by setting and clearing the
appropriate SSPM bits in SSPCON1 and by setting the
SSPEN bit. In Master mode, the SCL and SDA lines
are manipulated by the MSSP hardware.
Master mode of operation is supported by interrupt
generation on the detection of the Start and Stop
conditions. The Stop (P) and Start (S) bits are cleared
from a Reset or when the MSSP module is disabled.
Control of the I
set or the bus is Idle, with both the S and P bits clear.
In Firmware Controlled Master mode, user code
conducts all I
Stop bit conditions.
Once Master mode is enabled, the user has six
options.
1.
2.
3.
4.
5.
6.
FIGURE 17-16:
 2004 Microchip Technology Inc.
Assert a Start condition on SDA and SCL.
Assert a Repeated Start condition on SDA and
SCL.
Write
transmission of data/address.
Configure the I
Generate an Acknowledge condition at the end
of a received byte of data.
Generate a Stop condition on SDA and SCL.
SDA
SCL
MASTER MODE
to
2
C bus operations based on Start and
2
C bus may be taken when the P bit is
the
2
C port to receive data.
SSPBUF
MSSP BLOCK DIAGRAM (I
SDA in
Bus Collision
SCL in
register
Read
initiating
MSb
Write Collision Detect
end of XMIT/RCV
Start bit, Stop bit,
State Counter for
Clock Arbitration
Start bit Detect
Stop bit Detect
Acknowledge
SSPBUF
Generate
SSPSR
2
C™ MASTER MODE)
LSb
Write
The following events will cause SSP Interrupt Flag bit,
SSPIF, to be set (SSP interrupt if enabled):
• Start condition
• Stop condition
• Data transfer byte transmitted/received
• Acknowledge transmit
• Repeated Start
Clock
Data Bus
Shift
Note:
Internal
Set/Reset S, P, WCOL (SSPSTAT);
set SSPIF, BCLIF;
reset ACKSTAT, PEN (SSPCON2)
The MSSP module, when configured in
I
of events. For instance, the user is not
allowed to initiate a Start condition and
immediately write the SSPBUF register to
initiate transmission before the Start
condition is complete. In this case, the
SSPBUF will not be written to and the
WCOL bit will be set, indicating that a write
to the SSPBUF did not occur.
2
C Master mode, does not allow queueing
PIC18FXX8
SSPADD<6:0>
SSPM3:SSPM0
Generator
Baud
Rate
DS41159D-page 167