PIC12F639 Microchip Technology, PIC12F639 Datasheet - Page 103

• Manufacturer Part Number: PIC12F639
• Description: (PIC12F635 / PIC12F636 / PIC12F639) 8/14-PIN FLASH-BASED / 8-BIT CMOS MICROCONTROLLERS WITH NANOWATT TECHNOLOGY
• Manufacturer: Microchip Technology

FIGURE 11-17:
© 2005 Microchip Technology Inc.
LFDATA/RSSI/
MCU SPI Write Details:
1.
2.
3.
4.
5.
6.
7.
CCLK/SDIO
ALERT
SCLK/
Drive the AFE’s open collector ALERT output low.
•
Drop CS.
•
•
Change LFDATA/RSSI/CCLK/SDIO connected pin to output.
•
Clock in 16-bit SPI Write sequence - command, address, data and parity bit.
•
Change LFDATA/RSSI/CCLK/SDIO connected pin to input.
Raise CS to complete the SPI Write.
Change SCLK/ALERT back to input.
CS
to ensure no false clocks occur when CS drops
AFE SCLK/ALERT becomes SCLK input
LFDATA/RSSI/CCLK/SDIO becomes SDI input
driving SPI data
command, address, data and parity bit
(output)
ALERT
LFDATA
(output)
1
SPI WRITE SEQUENCE
(input)
2
SCLK
(input)
T
CSSC
SDI
T
3
SU
MSb
T
HD
4
16 Clocks for Write Command, Address and Data
PIC12F635/PIC16F636/639
Preliminary
T
HI
1/F
SCLK
T
LO
LSb
T
SCCS
5
6
T
LFDATA
(output)
CS
1
(output)
ALERT
DS41232B-page 101
T
7
CSH
T
CS
0