PIC16F872-I/SP Microchip Technology Inc., PIC16F872-I/SP Datasheet - Page 63

• 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

FIGURE 9-7:
9.2.2
The addressing procedure for the I
the first byte after the START condition usually deter-
mines which device will be the slave addressed by the
master. The exception is the general call address,
which can address all devices. When this address is
used, all devices should, in theory, respond with an
Acknowledge.
The general call address is one of eight addresses
reserved for specific purposes by the I
consists of all 0’s with R/W = 0.
The general call address is recognized when the Gen-
eral Call Enable bit (GCEN) is enabled (SSPCON2<7>
is set). Following a START bit detect, 8-bits are shifted
into SSPSR and the address is compared against
SSPADD. It is also compared to the general call
address and fixed in hardware.
FIGURE 9-8:
© 2006 Microchip Technology Inc.
SDA
SCL
SSPIF
BF (SSPSTAT<0>)
CKP (SSPCON<4>)
GCEN
(SSPCON2<7>)
SSPOV
(SSPCON<6>)
SDA
SCL
SSPIF
BF
(SSPSTAT<0>)
S
GENERAL CALL ADDRESS
SUPPORT
A7
1
Data in
sampled
S
A6
2
I
SLAVE MODE GENERAL CALL ADDRESS SEQUENCE (7 OR 10-BIT MODE)
2
C WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)
A5
Receiving Address
3
1
A4
4
2
General Call Address
A3
2
5
C bus is such that
3
A2
6
2
C protocol. It
4
A1
7
5
R/W = 1
8
6
9
ACK
responds to SSPIF
7
while CPU
SCL held low
R/W = 0
8
If the general call address matches, the SSPSR is
transferred to the SSPBUF, the BF flag is set (eighth
bit), and on the falling edge of the ninth bit (ACK bit),
the SSPIF flag is set.
When the interrupt is serviced, the source for the inter-
rupt can be checked by reading the contents of the
SSPBUF, to determine if the address was device spe-
cific or a general call address.
In 10-bit mode, the SSPADD is required to be updated
for the second half of the address to match, and the UA
bit is set (SSPSTAT<1>). If the general call address is
sampled when GCEN is set while the slave is config-
ured in 10-bit Address mode, then the second half of
the address is not necessary, the UA bit will not be set,
and the slave will begin receiving data after the
Acknowledge (Figure 9-8).
ACK
Address is compared to General Call Address
after ACK, set interrupt flag
9
D7
D7
1
SSPBUF is written in software
1
D6
Cleared in software
D6
2
2
Cleared in software
SSPBUF is read
Set bit after writing to SSPBUF
(the SSPBUF must be written to
before the CKP bit can be set)
D5
3
Receiving Data
D5
3
D4
4
D4
4
Transmitting Data
D3
5
D3
5
PIC16F872
D2
6
D2
6
From SSP Interrupt
Service Routine
D1
7
D1
7
D0
8
DS30221C-page 61
D0
8
Not ACK
R/W = 0
9
ACK
9
'0'
'1'
P