24-03-2014, 10:46 AM
PIC Microcontrollers
[attachment=60466]
PIC stands for Peripheral Interface Controller coined by Microchip Technology to identify its single-
chip microcontrollers. These devices have been phenomenally successful in 8-bit microcontroller mar-
ket. The main reason is that Microchip Technology has constantly upgraded the device architecture
and added needed peripherals to the microcontroller to ’suit customers’ requirements. The develop-
ment tools such as assembler and simulator are freely available on the internet at www.microchip.com
Low-end Architectures
Microchip PIC microcontrollers are available in various types. When P IC − M icro MCU first
became available from General Instruments in early 1980’s, the microcontroller consisted of a very
simple processor executing 12-bit wide instructions with basic I/O functions. These devices are known
as low-end architectures.
Some of the low-end device past numbers are
12C5XX, 16C5X, and 16C505
Data Communication protocol
In I2 C communication standard, there is one bus master and several slaves. It can be assumed here
that the PIC microcontroller is the bus master and several peripheral devices connected to SDA and
SCL bus are slaves.
Following a start condition, the master sends a 7-bit address of the slave on SDA line. The MSB
is sent first. After sending 7 bit address of the slave peripheral a R/W bit (8th bit) is sent by the
master. If R/W bit is 0 the following byte (after the acknowledgment) is written by the master to the
addressed slave peripheral. If R/W bit is 1, the following byte after the acknowledgment bit has to
be read from the slave by the master. After sending the 7-bit address of the slave, the master sends
the address of the internal register of the salve where from the data has to be used or written to. The
subsegment access is automatically directed to the next address of the internal register.
[attachment=60466]
PIC stands for Peripheral Interface Controller coined by Microchip Technology to identify its single-
chip microcontrollers. These devices have been phenomenally successful in 8-bit microcontroller mar-
ket. The main reason is that Microchip Technology has constantly upgraded the device architecture
and added needed peripherals to the microcontroller to ’suit customers’ requirements. The develop-
ment tools such as assembler and simulator are freely available on the internet at www.microchip.com
Low-end Architectures
Microchip PIC microcontrollers are available in various types. When P IC − M icro MCU first
became available from General Instruments in early 1980’s, the microcontroller consisted of a very
simple processor executing 12-bit wide instructions with basic I/O functions. These devices are known
as low-end architectures.
Some of the low-end device past numbers are
12C5XX, 16C5X, and 16C505
Data Communication protocol
In I2 C communication standard, there is one bus master and several slaves. It can be assumed here
that the PIC microcontroller is the bus master and several peripheral devices connected to SDA and
SCL bus are slaves.
Following a start condition, the master sends a 7-bit address of the slave on SDA line. The MSB
is sent first. After sending 7 bit address of the slave peripheral a R/W bit (8th bit) is sent by the
master. If R/W bit is 0 the following byte (after the acknowledgment) is written by the master to the
addressed slave peripheral. If R/W bit is 1, the following byte after the acknowledgment bit has to
be read from the slave by the master. After sending the 7-bit address of the slave, the master sends
the address of the internal register of the salve where from the data has to be used or written to. The
subsegment access is automatically directed to the next address of the internal register.