Datasheet

PICkit™ Serial Analyzer User’s Guide
DS51647C-page 114 © 2009 Microchip Technology Inc.
11.8 SPI COMMUNICATIONS
SPI is a 4-wire serial protocol that uses data in, data out, clock and Chip Select pins. It
is a very basic protocol using a clock edge to capture data. The CONTROL_BLOCK is
used to enable SPI event markers, set the bit rate and configure transaction/protocol
options.
TABLE 11-31: CONNECTOR PINOUT IN SPI MODE
TABLE 11-32: SPI CONTROL BLOCK
Note 1: CSPOL determines the ‘active’ state of CS
,
if CSPOL=0, CS
is active-low
if CSPOL=1, CS
is active-high
upon initialization, CS
is set ‘inactive’
Pin Description
1CS
2+V
3G
ND
4SDI
5SCK
6SDO
Byte Bit Description
Comm: SPI
16 7:0 Bit flags
0 1 = Event marker enable: read byte
1 1 = Event marker enable: write byte
2 1 = Event marker enable: status error
3 1 =
4 1 =
5 1 =
6 1 =
7 1 =
17 7:0 SPI Configuration bits
0 1 = SMP (sample phase)
1 1 = CKE (clock edge select)
2 1 = CKP (clock polarity)
3 1 = DAOD (disable auto output disable on data input)
4n/a
5n/a
6n/a
7 CSPOL (Chip Select Polarity), 0=Low TRUE, 1=High TRUE
(1)
18 7:0
19 7:0
20 7:0
21 7:0
22 7:0 BIT RATE: Pre-scale code
23 7:0 BIT RATE: Scaling code