PIC16F1933-ESLASHP datasheet(284/418 Pages) MICROCHIP

284 / 418 page

PIC16F193X/LF193X

DS41364A-page 282

Preliminary

22.3.3

ENABLING SPI I/O

To enable the serial port, SSP Enable bit, SSPEN of the

SSPCON1 register, must be set. To reset or reconfig-

ure SPI mode, clear the SSPEN bit, re-initialize the

SSPCONx registers and then set the SSPEN bit. This

configures the SDI, SDO, SCK and SS pins as serial

port pins. For the pins to behave as the serial port func-

tion, some must have their data direction bits (in the

TRIS register) appropriately programmed as follows:

• SDI must have corresponding TRIS bit set

• SDO must have corresponding TRIS bit cleared

• SCK (Master mode) must have corresponding

TRIS bit cleared

• SCK (Slave mode) must have corresponding

TRIS bit set

•SS must have corresponding TRIS bit set

Any serial port function that is not desired may be

overridden by programming the corresponding data

direction (TRIS) register to the opposite value.

22.3.4

TYPICAL CONNECTION

Figure 22-4 shows a typical connection between two

microcontrollers. The master controller (Processor 1)

initiates the data transfer by sending the SCK signal.

Data is shifted out of both shift registers on their pro-

grammed clock edge and latched on the opposite edge

of the clock. Both processors should be programmed to

the same Clock Polarity (CKP), then both controllers

would send and receive data at the same time.

Whether the data is meaningful (or dummy data)

depends on the application software. This leads to

three scenarios for data transmission:

• Master sends data (Slave sends dummy data)

• Master sends data (Slave sends data)

• Master sends dummy data (Slave sends data)

FIGURE 22-4:

SPI MASTER/SLAVE CONNECTION

Serial Input Buffer

(SSPBUF)

Shift Register

(SSPSR)

MSb

LSb

SDO

SDI

Processor 1

SCK

SPI Master SSPM<3:0> = 00xx

Serial Input Buffer

(SSPBUF)

Shift Register

(SSPSR)

LSb

MSb

SDI

SDO

Processor 2

SCK

SPI Slave SSPM<3:0> = 010x

Serial Clock

Slave Select

General I/O

(optional)

= 1010

PIC16F1933-E/P Datasheet(PDF) 284 Page - Microchip Technology

PIC16F1933-E/P Datasheet(HTML) 284 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL