PIC18F6490-E/PT Microchip Technology, PIC18F6490-E/PT Datasheet - Page 162

• Manufacturer Part Number: PIC18F6490-E/PT
• Description: IC PIC MCU FLASH 16KX16 64TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F6490-E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, LCD, POR, PWM, WDT
• Number Of I /o: 50
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 64-TFQFP
• For Use With: DM163028 - BOARD DEMO PICDEM LCD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

PIC18F6390/6490/8390/8490
15.3.2
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSPCON1<5:0> and SSPSTAT<7:6>).
These control bits allow the following to be specified:
• Master mode (SCK is the clock output)
• Slave mode (SCK is the clock input)
• Clock Polarity (Idle state of SCK)
• 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)
The MSSP consists of a Transmit/Receive Shift regis-
ter (SSPSR) and a Buffer register (SSPBUF). The
SSPSR shifts the data in and out of the device, MSb
first. The SSPBUF holds the data that was written to the
SSPSR until the received data is ready. Once the 8 bits
of data have been received, that byte is moved to the
SSPBUF register. Then, the Buffer Full detect bit, BF
(SSPSTAT<0>), and the interrupt flag bit, SSPIF, are
set. This double-buffering of the received data
(SSPBUF) allows the next byte to start reception before
EXAMPLE 15-1:
DS39629C-page 160
LOOP
output time)
SCK)
BTFSS
BRA
MOVF
MOVWF
MOVF
MOVWF
OPERATION
SSPSTAT, BF
LOOP
SSPBUF, W
RXDATA
TXDATA, W
SSPBUF
LOADING THE SSPBUF (SSPSR) REGISTER
;Has data been received (transmit complete)?
;No
;WREG reg = contents of SSPBUF
;Save in user RAM, if data is meaningful
;W reg = contents of TXDATA
;New data to xmit
reading the data that was just received. Any write to the
SSPBUF register during transmission/reception of data
will be ignored and the Write Collision Detect bit,
WCOL (SSPCON1<7>), will be set. User software
must clear the WCOL bit so that it can be determined if
the following write(s) to the SSPBUF register
completed successfully.
When the application software is expecting to receive
valid data, the SSPBUF should be read before the next
byte of data to transfer is written to the SSPBUF. The
Buffer Full bit, BF (SSPSTAT<0>), indicates when
SSPBUF has been loaded with the received data
(transmission is complete). When the SSPBUF 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 SSPBUF must be read and/or
written. If the interrupt method is not going to be used,
then software polling can be done to ensure that a write
collision does not occur. Example 15-1 shows the
loading of the SSPBUF (SSPSR) for data transmission.
The SSPSR is not directly readable or writable and can
only be accessed by addressing the SSPBUF register.
Additionally, the MSSP Status register (SSPSTAT)
indicates the various status conditions.
© 2007 Microchip Technology Inc.