PIC16F872-I/SP Microchip Technology Inc., PIC16F872-I/SP Datasheet - Page 68

• Manufacturer Part Number: PIC16F872-I/SP
• Description: 28 PIN, 7 KB FLASH, 128 RAM, 22 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F872-I/SP

• A/d Inputs: 5-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 22
• Interface: I2C/SPI
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16F872
9.2.10
A Repeated START condition occurs when the RSEN
bit (SSPCON2<1>) is programmed high and the I
module is in the IDLE state. When the RSEN bit is set,
the SCL pin is asserted low. When the SCL pin is sam-
pled low, the baud rate generator is loaded with the
contents of SSPADD<6:0> and begins counting. The
SDA pin is released (brought high) for one baud rate
generator count (T
times out if SDA is sampled high, the SCL pin will be
de-asserted (brought high). When SCL is sampled
high, the baud rate generator is reloaded with the con-
tents of SSPADD<6:0> and begins counting. SDA and
SCL must be sampled high for one T
then followed by assertion of the SDA pin (SDA is low)
for one T
RSEN bit in the SSPCON2 register will be automati-
cally cleared and the baud rate generator will not be
reloaded, leaving the SDA pin held low. As soon as a
START condition is detected on the SDA and SCL pins,
the S bit (SSPSTAT<3>) will be set. The SSPIF bit will
not be set until the baud rate generator has timed out.
FIGURE 9-13:
DS30221C-page 66
Note 1: If RSEN is programmed while any other
2: A bus collision during the Repeated
BRG
I
START CONDITION TIMING
event is in progress, it will not take effect.
2
START condition occurs if:
• SCL goes low before SDA is
• SDA is sampled low when SCL
C MASTER MODE REPEATED
, while SCL is high. Following this, the
goes from low to high.
asserted low. This may indicate that
another master is attempting to
transmit a data "1".
Falling edge of ninth clock
BRG
). When the baud rate generator
REPEAT START CONDITION WAVEFORM
SDA
SCL
End of Xmit
Write to SSPCON2
occurs here.
SDA = 1,
SCL(no change).
BRG
. This action is
2
C
T
SDA = 1,
SCL = 1
BRG
T
BRG
Immediately following the SSPIF bit getting set, the
user may write the SSPBUF with the 7-bit address in
7-bit mode, or the default first address in 10-bit mode.
After the first eight bits are transmitted and an ACK is
received, the user may then transmit an additional eight
bits of address (10-bit mode), or eight bits of data (7-bit
mode).
9.2.10.1
If the user writes the SSPBUF when a Repeated
START sequence is in progress, then WCOL is set and
the contents of the buffer are unchanged (the write
doesn’t occur).
Note:
Sr = Repeated START
T
BRG
At completion of START bit,
hardware clear RSEN bit
Set S (SSPSTAT<3>)
Because queueing of events is not
allowed, writing of the lower 5 bits of
SSPCON2 is disabled until the Repeated
START condition is complete.
and set SSPIF
Write to SSPBUF occurs here
T
WCOL Status Flag
BRG
1st Bit
T
BRG
© 2006 Microchip Technology Inc.