Add code & schematic for 48-channel I2C multiplexer

2026-03-21 01:00:57 +03:00 · 2018-05-20 17:34:19 +03:00
parent 49a2a231b7
commit 4e74e1121b
21 changed files with 5516 additions and 135 deletions
--- a/STM32/src4multiplexer/hardware.c
+++ b/STM32/src4multiplexer/hardware.c
@@ -0,0 +1,66 @@
+/*
+ *                                                                                                  geany_encoding=koi8-r
+ * hardware.c - hardware-dependent macros & functions
+ *
+ * Copyright 2018 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ *
+ */
+
+#include "hardware.h"
+
+void gpio_setup(void){
+    // Set green led (PB3) as output
+    RCC->AHBENR |= RCC_AHBENR_GPIOBEN | RCC_AHBENR_GPIOAEN;
+    GPIOB->MODER = GPIO_MODER_MODER3_O;
+    // setup of multiplexer channel address bus: PA3..8
+    GPIOA->MODER = GPIO_MODER_MODER3_O | GPIO_MODER_MODER4_O | GPIO_MODER_MODER5_O |
+                   GPIO_MODER_MODER6_O | GPIO_MODER_MODER7_O | GPIO_MODER_MODER8_O;
+}
+
+void i2c_setup(I2C_SPEED speed){
+    I2C1->CR1 = 0;
+#if I2CPINS == A9A10
+/*
+ * GPIO Resources: I2C1_SCL - PA9, I2C1_SDA - PA10
+ * GPIOA->AFR[1] AF4 -- GPIOA->AFR[1] &= ~0xff0, GPIOA->AFR[1] |= 0x440
+ */
+    RCC->AHBENR |= RCC_AHBENR_GPIOAEN; // clock
+    GPIOA->AFR[1] &= ~0xff0; // alternate function F4 for PA9/PA10
+    GPIOA->AFR[1] |= 0x440;
+    GPIOA->MODER &= ~(GPIO_MODER_MODER9 | GPIO_MODER_MODER10);
+    GPIOA->MODER |= GPIO_MODER_MODER9_AF | GPIO_MODER_MODER10_AF; // alternate function
+    GPIOA->OTYPER |= GPIO_OTYPER_OT_9 | GPIO_OTYPER_OT_10; // opendrain
+    //GPIOA->OTYPER |= GPIO_OTYPER_OT_10; // opendrain
+#else // undefined
+#error "Not implemented"
+#endif
+    // I2C
+    RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // timing
+    RCC->CFGR3 |= RCC_CFGR3_I2C1SW; // use sysclock for timing
+    if(speed == LOW_SPEED){ // 10kHz
+        // PRESC=B, SCLDEL=4, SDADEL=2, SCLH=0xC3, SCLL=0xC7
+        //I2C1->TIMINGR = (0xB<<28) | (4<<20) | (2<<16) | (0xC3<<8) | (0xC7);
+        I2C1->TIMINGR = (0xB<<28) | (4<<20) | (2<<16) | (0xC3<<8) | (0xB0);
+    }else{ // 100kHz
+        // Clock = 6MHz, 0.16(6)us, need 5us (*30)
+        // PRESC=4 (f/5), SCLDEL=0 (t_SU=5/6us), SDADEL=0 (t_HD=5/6us), SCLL,SCLH=14 (2.(3)us)
+        //I2C1->TIMINGR = (4<<28) | (14<<8) | (14); // 0x40000e0e
+        I2C1->TIMINGR = (0xB<<28) | (4<<20) | (2<<16) | (0x12<<8) | (0x11);
+    }
+    I2C1->CR1 = I2C_CR1_PE;// | I2C_CR1_RXIE; // Enable I2C & (interrupt on receive - not supported yet)
+}