我一直在审查Microchip PIC16LF15344数据表中的外设引脚选择，要么我正在读错，要么它似乎在文档中有错误和不一致。我想知道是否有其他人使用过该设备并确认我的解释。
我正在尝试为PIC16LF15344编写代码以使用I2C接口。我已经设法为I2C写了PIC16LF1822代码工作正常，但我到目前为止无法在PIC16LF15344上工作，并且数据表中有一些令人困惑的文档我想要清理。
这是对datasheet的引用。
pinout的PIC16LF15344描述表明I2C SDA函数可以分配给RC1或RB6。同样，I2C SCL可能被分配给RC0或RB4。但是Section 15.3 Bidirectional Pins有一个注释如下。
I2C SCLx和SDAx函数可以通过PPS重新映射。然而，只有RB1，RB2，RC3和RC4品脱有I2C和SMBus特定的输入缓冲区实现（I2C模式禁用INLVL并设置特定于I2C的阈值）。如果SCLx或SDAx函数映射到某些其他引脚（RB1，RB2，RC3或RC4除外），则将使用通用TTL或ST输入缓冲区（基于INLVL寄存器设置配置）。因此，在大多数应用中，建议仅将SCLx和SDAx引脚函数映射到RB1，RB2，RC3或RC4引脚。
问题不仅在于说明似乎与引脚分配表中的描述相冲突，它还引用了引脚RB1和RB2，它们没有出现在引脚分配表中的任何位置，即它们似乎不存在这PIC。我看到类似于RB1和RB2的脚注，但它们没有记录在文档正文或表格的任何地方。
当然这必须是文档错误，但我在PIC16LF15324/44数据表上找不到当前的勘误表来纠正这个问题。我看对了吗？
我已经尝试将SCL和SDA与PPS配置到引脚RC0和RC1，因为这是它们如何连接到我的PCB，但我无法使用I2C工作，但使用的工具基本上与我用于PIC16LF1822的软件相同。 PPS和EUSART TX2的RX2默认值是RC0和RC1。这是否意味着我需要使用TX2CKPPS和RX2DTPPS在使用EUSART和SSP1CLKPPS将SSP1DATPPS和SCL分配给SDA和RC0之前移动RC1作业。
我将调查我的PCB的其他潜在问题，但我想在我提交另一个PCB为fab之前理顺这个问题。无论如何我需要进行一些更改，所以我可能只需将SCL和SDA连接到下一版本的PPS默认值，然后再试一次。
这是初始化代码：
OSCFRQbits.HFFRQ = 0b011; // Set internal HF oscillator frequency to 8 MHz
WPUA = 0b00111111; // Enable all weak pull-up resistors on port A
WPUB = 0b11110000; // Enable all weak pull-up resistors on port B
WPUC = 0b11111100; // Enable all weak pull-up resistors on port C except
// RC0 and RC1 to be used as I2C SCL and SDA
TRISA = 0b00110000; // Set RA4 and RA5 as inputs
ANSELA = 0b00110000; // Set RA4 and RA5 to analog
TRISB = 0b00110000; // Set RB6 and RB7 as inputs
ANSELB = 0b11000000; // Set RB6 and RB7 as analog
TRISC = 0b11111011; // Set RC0, RC1, RC3, RC4, RC5, RC6, and RC7 as inputs
ANSELC = 0b11111000; // Set RC3, RC4, RC5, RC6, and RC7 as analog
TX2CKPPS = 0b01100; // Use RB4 for TX2
RX2DTPPS = 0b01110; // Use RB6 for RX2
SSP1CLKPPS = 0b10000; // Use RC0 as SCL
SSP1DATPPS = 0b10001; // Use RC1 as SDA
SSP1CON1 = 0b00100110; // SSPEN enabled, WCOL no collision, SSPOV no overflow,
// CKP low hold, SSPM I2C slave 7-bit
SSP1CON2 = 0b00000000; // ACKSTAT received, RCEN disabled, RSEN disabled,
// ACKEN disabled, ACKDT acknowledge, SEN disabled,
// GCEN disabled, PEN disabled
SSP1CON3 = 0b00000000; // BOEN disabled, AHEN disabled, SBCDE disabled,
// SDAHT 100 ns hold, ACKTIM ackseq, DHEN disabled,
// PCIE disabled, SCIE disabled
SSP1STAT = 0x00;
SSP1BUF = 0x00;
SSP1MSK = 0xff;
SSP1ADD = I2C_SLAVE_ADDR << 1;
PIR3bits.SSP1IF = 0; // Clear the SSP Interrupt flag
PIE3bits.SSP1IE = 1; // Enable SSP Interrupts
INTCONbits.GIE = 1; // Enable global interrupts
INTCONbits.PEIE = 1; // Enable peripheral interrupts
您可能有几个问题需要处理。
所有默认的I2C引脚也具有模拟功能。确保与ANSB引脚相关的ANSC或I2C位设置为数字操作。
虽然上电复位选择I2C输入引脚分配的数据表默认值，但默认情况下I2C输出不会分配给任何GPIO引脚。您需要将I2C和SCL的SDA输出放在正确的PPS映射寄存器中。
请注意，无论I2C主机或从机实现如何，输入和输出功能都应映射到同一引脚。
编辑您的问题并发布用于初始化I2C引脚和PPS映射寄存器的代码将有所帮助。
/*
* File: main.c
* PIC16LF15354
* +-------------:_:-------------+
* 10K Pull-Up -> 1 : RE3/MCLR ANB7/RX2/PGD/RB7 : 28 <>
* <> 2 : RA0/ANA0 ANB6/TX2/PGC/RB6 : 27 <> RX2
* <> 3 : RA1/ANA1 ANB5/RB5 : 26 <>
* <> 4 : RA2/ANA2 ANB4/RB4 : 25 <> TX2
* <> 5 : RA3/ANA3 ANB3/RB3 : 24 <>
* <> 6 : RA4/ANA4 ANB2/SDA2/RB2 : 23 <>
* <> 7 : RA5/ANA5 ANB1/SCL2/RB1 : 22 <>
* GND -> 8 : VSS ANB0/RB0 : 21 <>
* <> 9 : RA7/OSC1/ANA7 VDD : 20 <- 3v3
* <> 10 : RA6/OSC2/ANA6 VSS : 19 <- GND
* SCL1 <> 11 : RC0/ANC0 ANC7/RX1/RC7 : 18 <>
* SDA1 <> 12 : RC1/ANC1 ANC6/TX1/RC6 : 17 <>
* <> 13 : RC2/ANC2 ANC5/RC5 : 16 <>
* <> 14 : RC3/SCL1/ANC3 ANC4/SDA1/RC4 : 15 <>
* +-----------------------------:
* DIP-28
*
* Created on January 4, 2019, 6:20 PM
*/
// PIC16LF15354 Configuration Bit Settings
#pragma config FEXTOSC = OFF // External Oscillator mode selection bits (Oscillator not enabled)
#pragma config RSTOSC = HFINT32 // Power-up default value for COSC bits (HFINTOSC with OSCFRQ= 32 MHz and CDIV = 1:1)
#pragma config CLKOUTEN = OFF // Clock Out Enable bit (CLKOUT function is disabled; i/o or oscillator function on OSC2)
#pragma config CSWEN = ON // Clock Switch Enable bit (Writing to NOSC and NDIV is allowed)
#pragma config FCMEN = OFF // Fail-Safe Clock Monitor Enable bit (FSCM timer disabled)
#pragma config MCLRE = ON // Master Clear Enable bit (MCLR pin is Master Clear function)
#pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config LPBOREN = OFF // Low-Power BOR enable bit (ULPBOR disabled)
#pragma config BOREN = OFF // Brown-out reset enable bits (Brown-out reset disabled)
#pragma config BORV = LO // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (VBOR) set to 1.9V on LF, and 2.45V on F Devices)
#pragma config ZCD = OFF // Zero-cross detect disable (Zero-cross detect circuit is disabled at POR.)
#pragma config PPS1WAY = OFF // Peripheral Pin Select one-way control (The PPSLOCK bit can be set and cleared repeatedly by software)
#pragma config STVREN = ON // Stack Overflow/Underflow Reset Enable bit (Stack Overflow or Underflow will cause a reset)
#pragma config WDTCPS = WDTCPS_31// WDT Period Select bits (Divider ratio 1:65536; software control of WDTPS)
#pragma config WDTE = SWDTEN // WDT operating mode (WDT enabled/disabled by SWDTEN bit in WDTCON0)
#pragma config WDTCWS = WDTCWS_7// WDT Window Select bits (window always open (100%); software control; keyed access not required)
#pragma config WDTCCS = SC // WDT input clock selector (Software Control)
#pragma config BBSIZE = BB512 // Boot Block Size Selection bits (512 words boot block size)
#pragma config BBEN = OFF // Boot Block Enable bit (Boot Block disabled)
#pragma config SAFEN = OFF // SAF Enable bit (SAF disabled)
#pragma config WRTAPP = OFF // Application Block Write Protection bit (Application Block not write protected)
#pragma config WRTB = OFF // Boot Block Write Protection bit (Boot Block not write protected)
#pragma config WRTC = OFF // Configuration Register Write Protection bit (Configuration Register not write protected)
#pragma config WRTSAF = OFF // Storage Area Flash Write Protection bit (SAF not write protected)
#pragma config LVP = OFF // Low Voltage Programming Enable bit (High Voltage on MCLR/Vpp must be used for programming)
#pragma config CP = OFF // UserNVM Program memory code protection bit (UserNVM code protection disabled)
#include <xc.h>
#define I2C_SLAVE_ADDR 0x00
void main(void)
{
WPUA = 0b00111111; // Enable all weak pull-up resistors on port A
WPUB = 0b11110000; // Enable all weak pull-up resistors on port B
WPUC = 0b11111100; // Enable all weak pull-up resistors on port C except
// RC0 and RC1 to be used as I2C SCL and SDA
TRISA = 0b00110000; // Set RA4 and RA5 as inputs
ANSELA = 0b00110000; // Set RA4 and RA5 to analog
TRISB = 0b00110000; // Set RB6 and RB7 as inputs
ANSELB = 0b11000000; // Set RB6 and RB7 as analog
TRISC = 0b11111011; // Set RC0, RC1, RC3, RC4, RC5, RC6, and RC7 as inputs
ANSELC = 0b11111000; // Set RC3, RC4, RC5, RC6, and RC7 as analog
#ifdef WRONG_WAY_TO_DO_PPS
TX2CKPPS = 0b01100; // Use RB4 for TX2
RX2DTPPS = 0b01110; // Use RB6 for RX2
SSP1CLKPPS = 0b10000; // Use RC0 as SCL
SSP1DATPPS = 0b10001; // Use RC1 as SDA
#else
RB4PPS = 0x11; // Assign TX2 output to RB4
RX2DTPPS = 0x0E; // Assign RB6 to RX2 input
RC0PPS = 0x15; // Assign SCL1 output to RC0
SSP1CLKPPS = 0x10; // Assign RC0 to SCL1 input
RC1PPS = 0x16; // Assign SDA1 output to RC1
SSP1DATPPS = 0x11; // Assign RC1 to SDA1 input
#endif
SSP1CON1 = 0b00100110; // SSPEN enabled, WCOL no collision, SSPOV no overflow,
// CKP low hold, SSPM I2C slave 7-bit
SSP1CON2 = 0b00000000; // ACKSTAT received, RCEN disabled, RSEN disabled,
// ACKEN disabled, ACKDT acknowledge, SEN disabled,
// GCEN disabled, PEN disabled
SSP1CON3 = 0b00000000; // BOEN disabled, AHEN disabled, SBCDE disabled,
// SDAHT 100 ns hold, ACKTIM ackseq, DHEN disabled,
// PCIE disabled, SCIE disabled
SSP1STAT = 0x00;
SSP1BUF = 0x00;
SSP1MSK = 0xff;
SSP1ADD = I2C_SLAVE_ADDR << 1;
PIR3bits.SSP1IF = 0; // Clear the SSP Interrupt flag
PIE3bits.SSP1IE = 1; // Enable SSP Interrupts
INTCONbits.GIE = 1; // Enable global interrupts
INTCONbits.PEIE = 1; // Enable peripheral interrupts
/*
* Embedded code never returns from main
*/
for(;;)
{
}
}
PPS设置正确但我不知道I2C初始化代码是否正确。