2002 Microchip Technology Inc.
Preliminary
DS30485A-page 129
PIC18FXX39
16.3.3
ENABLING SPI I/O
To enable the serial port, SSP Enable bit, SSPEN
(SSPCON1<5>), must be set. To reset or reconfigure
SPI mode, clear the SSPEN bit, re-initialize the
SSPCON 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. That is:
SDI is automatically controlled by the SPI module
SDO must have TRISC<5> bit cleared
SCK (Master mode) must have TRISC<3> bit
cleared
SCK (Slave mode) must have TRISC<3> bit set
SS must have TRISC<4> 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.
16.3.4
TYPICAL CONNECTION
Figure 16-2 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 pro-
grammed 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 16-2:
SPI MASTER/SLAVE CONNECTION
Serial Input Buffer
(SSPBUF)
Shift Register
(SSPSR)
MSb
LSb
SDO
SDI
PROCESSOR 1
SCK
SPI Master SSPM3:SSPM0 = 00xxb
Serial Input Buffer
(SSPBUF)
Shift Register
(SSPSR)
LSb
MSb
SDI
SDO
PROCESSOR 2
SCK
SPI Slave SSPM3:SSPM0 = 010xb
Serial Clock
相关PDF资料
XF2J-2824-11 CONN FPC 28POS 0.5MM SMT
PIC18F4439T-E/PT IC PIC MCU FLASH 6KX16 44TQFP
PIC18F6585T-I/PT IC PIC MCU FLASH 24KX16 64TQFP
PIC18LF8525T-I/PT IC PIC MCU FLASH 24KX16 80TQFP
PIC18F6720T-E/PT IC PIC MCU FLASH 64KX16 64TQFP
PIC18F4539T-E/PT IC PIC MCU FLASH 12KX16 44TQFP
PIC16F685-I/P IC PIC MCU FLASH 4KX14 20DIP
PIC16F689-I/P IC PIC MCU FLASH 4KX14 20DIP
相关代理商/技术参数
PIC18F4439T-E/PT 功能描述:8位微控制器 -MCU MCU CMOS RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4439T-I/ML 功能描述:8位微控制器 -MCU 12KB 640 RAM 32 I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4439T-I/PT 功能描述:8位微控制器 -MCU 12KB 640 RAM 32 I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4450-I/ML 功能描述:8位微控制器 -MCU 16KB FL 768 RAM 34 I/O FS-USB 2.0 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4450-I/P 功能描述:8位微控制器 -MCU 16KB FL 768 RAM 34 I/O FS-USB 2.0 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4450-I/PT 功能描述:8位微控制器 -MCU 16KB FL 768 RAM 34 I/O FS-USB 2.0 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4450T-I/ML 功能描述:8位微控制器 -MCU 16KB FL 768 RAM 34 I/O FS-USB 2.0 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F4450T-I/PT 功能描述:8位微控制器 -MCU 16KB FL 768 RAM 34 I/O FS-USB 2.0 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT