PIC18F45J10-I/ML Microchip Technology Inc., PIC18F45J10-I/ML Datasheet - Page 150

• Manufacturer Part Number: PIC18F45J10-I/ML
• Description: 44 PIN, 32 KB FLASH, 1024 RAM
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F45J10-I/ML

• A/d Inputs: 13-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 32
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin QFN
• Programmable Memory: 32K Bytes
• Ram Size: 1K Bytes
• Speed: 40 MHz
• Timers: 1-8 bit, 2-16 bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC18F45J10 FAMILY
15.3.2
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPxCON1<5:0> and SSPxSTAT<7:6>).
These control bits allow the following to be specified:
• Master mode (SCKx is the clock output)
• Slave mode (SCKx is the clock input)
• Clock Polarity (Idle state of SCKx)
• Data Input Sample Phase (middle or end of data
• Clock Edge (output data on rising/falling edge of
• Clock Rate (Master mode only)
• Slave Select mode (Slave mode only)
Each MSSP consists of a transmit/receive shift register
(SSPxSR) and a buffer register (SSPxBUF). The
SSPxSR shifts the data in and out of the device, MSb
first. The SSPxBUF holds the data that was written to the
SSPxSR until the received data is ready. Once the 8 bits
of data have been received, that byte is moved to the
SSPxBUF register. Then, the Buffer Full detect bit BF
(SSPxSTAT<0>) and the interrupt flag bit SSPxIF are
set. This double-buffering of the received data
(SSPxBUF) allows the next byte to start reception before
reading the data that was just received. Any write to the
EXAMPLE 15-1:
DS39682B-page 148
LOOP
output time)
SCKx)
BTFSS
BRA
MOVF
MOVWF
MOVF
MOVWF
OPERATION
SSP1STAT, BF
LOOP
SSP1BUF, W
RXDATA
TXDATA, W
SSP1BUF
LOADING THE SSP1BUF (SSP1SR) REGISTER
;Has data been received (transmit complete)?
;No
;WREG reg = contents of SSP1BUF
;Save in user RAM, if data is meaningful
;W reg = contents of TXDATA
;New data to xmit
Preliminary
successfully.
written. If the interrupt method is not going to be used,
loading
SSPxBUF register during transmission/reception of data
will be ignored and the Write Collision detect bit, WCOL
(SSPxCON1<7>), will be set. User software must clear
the WCOL bit so that it can be determined if the following
write(s)
When the application software is expecting to receive
valid data, the SSPxBUF should be read before the next
byte of data to transfer is written to the SSPxBUF. The
Buffer Full bit, BF (SSPxSTAT<0>), indicates when
SSPxBUF has been loaded with the received data
(transmission is complete). When the SSPxBUF is read,
the BF bit is cleared. This data may be irrelevant if the
SPI is only a transmitter. Generally, the MSSP interrupt
is used to determine when the transmission/reception
has completed. The SSPxBUF must be read and/or
then software polling can be done to ensure that a write
collision does not occur. Example 15-1 shows the
transmission.
The SSPxSR is not directly readable or writable and
can only be accessed by addressing the SSPxBUF
register. Additionally, the SSPxSTAT register indicates
the various status conditions.
of
to
the
the
SSP1BUF
SSPxBUF
© 2006 Microchip Technology Inc.
(SSP1SR)
register
completed
for
data