SPI发送移位数据出错

您好。我正在编写一个代码，通过SPI连接一个7HC595到PIC18F2550。一切都很好，然后我把把数据发送到595的部分移到一个函数中，出现了问题。首先，这里是实际的代码：Anim创建了一个光效（LED连接到7HC595）。它应该使LED从QA的595到QH，然后从QA转向QH，创建一个简单的追赶者。这种效应是正确的，尽管它正在从QC转向QH，然后转向QA和QB（以同样的方式关闭）。就像数据被“转移”了，我不知道为什么！我已经测试了WCOL位并且没有出错（从来没有被设置）。RCLK是寄存器时钟，如果是595。PIC时钟源为锁相环的48兆赫输出，20MHz的晶体馈电。在PIC和7HC595附近去耦上限（100NF）。我写了一个更简单的代码，没有SPIX写函数（函数内部的代码在（1）循环中）和for循环（I是用IF语句的一个简单的测试来增加或清除“i”值），它是按预期工作的。为什么我的数据移动了？？？？？



      以下为原文

    Hello.
I was writting a code to connect a 74HC595 to PIC18F2550 via SPI. Everthing was working fine, then I moved the part of the main that send the data to 595 to a function, and problems appeared.
First, here is the actual code:

/*
* File:   main.c
* Author: Stephen
*
* Created on 3 de Julho de 2017, 09:49
*/
// PIC18F2550 Configuration Bit Settings
// 'C' source line config statements
// CONFIG1L
#pragma config PLLDIV = 5       // PLL Prescaler Selection bits (Divide by 5 (20 MHz oscillator input))
#pragma config CPUDIV = OSC1_PLL2// System Clock Postscaler Selection bits ([Primary Oscillator Src: /1][96 MHz PLL Src: /2])
#pragma config USBDIV = 1       // USB Clock Selection bit (used in Full-Speed USB mode only; UCFG:FSEN = 1) (USB clock source comes directly from the primary oscillator block with no postscale)
// CONFIG1H
#pragma config FOSC = HSPLL_HS  // Oscillator Selection bits (HS oscillator, PLL enabled (HSPLL))
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF       // Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)
// CONFIG2L
#pragma config PWRT = ON        // Power-up Timer Enable bit (PWRT enabled)
#pragma config BOR = ON         // Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only (SBOREN is disabled))
#pragma config BORV = 0         // Brown-out Reset Voltage bits (Maximum setting 4.59V)
#pragma config VREGEN = OFF     // USB Voltage Regulator Enable bit (USB voltage regulator disabled)
// CONFIG2H
#pragma config WDT = OFF        // Watchdog Timer Enable bit (WDT disabled (control is placed on the SWDTEN bit))
#pragma config WDTPS = 32768    // Watchdog Timer Postscale Select bits (1:32768)
// CONFIG3H
#pragma config CCP2MX = ON      // CCP2 MUX bit (CCP2 input/output is multiplexed with RC1)
#pragma config PBADEN = OFF     // PORTB A/D Enable bit (PORTB<4:0> pins are configured as digital I/O on Reset)
#pragma config LPT1OSC = OFF    // Low-Power Timer 1 Oscillator Enable bit (Timer1 configured for higher power operation)
#pragma config MCLRE = ON       // MCLR Pin Enable bit (MCLR pin enabled; RE3 input pin disabled)
// CONFIG4L
#pragma config STVREN = ON      // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config LVP = OFF        // Single-Supply ICSP Enable bit (Single-Supply ICSP disabled)
#pragma config XINST = OFF      // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))
// CONFIG5L
#pragma config CP0 = OFF        // Code Protection bit (Block 0 (000800-001FFFh) is not code-protected)
#pragma config CP1 = OFF        // Code Protection bit (Block 1 (002000-003FFFh) is not code-protected)
#pragma config CP2 = OFF        // Code Protection bit (Block 2 (004000-005FFFh) is not code-protected)
#pragma config CP3 = OFF        // Code Protection bit (Block 3 (006000-007FFFh) is not code-protected)
// CONFIG5H
#pragma config CPB = OFF        // Boot Block Code Protection bit (Boot block (000000-0007FFh) is not code-protected)
#pragma config CPD = OFF        // Data EEPROM Code Protection bit (Data EEPROM is not code-protected)
// CONFIG6L
#pragma config WRT0 = OFF       // Write Protection bit (Block 0 (000800-001FFFh) is not write-protected)
#pragma config WRT1 = OFF       // Write Protection bit (Block 1 (002000-003FFFh) is not write-protected)
#pragma config WRT2 = OFF       // Write Protection bit (Block 2 (004000-005FFFh) is not write-protected)
#pragma config WRT3 = OFF       // Write Protection bit (Block 3 (006000-007FFFh) is not write-protected)
// CONFIG6H
#pragma config WRTC = OFF       // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) are not write-protected)
#pragma config WRTB = OFF       // Boot Block Write Protection bit (Boot block (000000-0007FFh) is not write-protected)
#pragma config WRTD = OFF       // Data EEPROM Write Protection bit (Data EEPROM is not write-protected)
// CONFIG7L
#pragma config EBTR0 = OFF      // Table Read Protection bit (Block 0 (000800-001FFFh) is not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF      // Table Read Protection bit (Block 1 (002000-003FFFh) is not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF      // Table Read Protection bit (Block 2 (004000-005FFFh) is not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF      // Table Read Protection bit (Block 3 (006000-007FFFh) is not protected from table reads executed in other blocks)
// CONFIG7H
#pragma config EBTRB = OFF      // Boot Block Table Read Protection bit (Boot block (000000-0007FFh) is not protected from table reads executed in other blocks)
#define _XTAL_FREQ 48000000
#include
#include "delays.h"
#define RCLK LATB0
const unsigned char anim[16] =
{0, 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F, 0x7F, 0xFF,
0xFE, 0xFC, 0xF8, 0xF0, 0xE0, 0xC0, 0x80};
void SPI_Write(unsigned char data)
{
    SSPBUF = data;
    while(!SSPIF);
    RCLK = 1;
    __delay_us(1);
    RCLK = 0;
    __delay_us(1);
}
void main(void)
{
    unsigned char i;
    TRISC = 0;
    TRISB = 0;
    SSPSTAT = 0x40;
    SSPCON1 = 0x20;
    SSPIF = 0;
    __delay_ms(100);
    while(1)
    {
        for(i = 0; i < 16; i++)
        {
            SPI_Write(anim);
            delay_ms(50);
        }
        for(i = 15; i > 0; i--)
        {
            SPI_Write(anim);
            delay_ms(50);
        }
    }
}


Anim creates a patern of light effect (LEDs are connected to 74HC595). It should turn LEDs on from QA of 595 to QH and then turn of from QA to QH, creating a simple chaser. The effect is right, despite it's turning on from QC to QH and then QA and QB (turning off the same way). It's like data was "shifted", and I have no idea why! I already tested WCOL bit and got nothing wrong (never was set).
RCLK is the register clock if 595. PIC Clock source is 48MHz output of PLL, fed by 20MHz Crystal. Decoupling caps (100nF) near PIC and 74HC595.
I wrote before a simpler code, without SPI_Write function (the code inside function was inside while(1) loop) and for loop (I was using a simple test with if statement to increment or clear "i" value) and it was working as expected.
Why is my data shifted???

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