Move allegedly unsafe afio->mapr RMW

keirf · Dec 3, 2019 · 512d557 · 512d557
1 parent 8ab2e4f
commit 512d557
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Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/src/amiga.c b/src/amiga.c
@@ -155,7 +155,7 @@ void amiga_init(void)
 
     /* We map PB4 (KBCLK) to TIM3,CH1 and use its input filter and edge 
      * detector to generate interrupts on clock transitions. */
-    afio->mapr |= AFIO_MAPR_TIM3_REMAP_PARTIAL;
+
     /* f_sampling = 72MHz/8 = 9MHz, N=8 -> must be stable for 889us. */
     tim3->ccmr1 = TIM_CCMR1_CC1S(TIM_CCS_INPUT_TI1) | TIM_CCMR1_IC1F(9);
     tim3->ccer = TIM_CCER_CC1E | TIM_CCER_CC1P; /* Falling edge */

diff --git a/src/stm32f10x.c b/src/stm32f10x.c
@@ -135,8 +135,11 @@ static void peripheral_init(void)
 
     rcc->ahbenr = RCC_AHBENR_DMA1EN;
 
-    /* Turn off serial-wire JTAG and reclaim the GPIOs. */
-    afio->mapr = AFIO_MAPR_SWJ_CFG_JTAGDISABLE;
+    /* Turn off serial-wire JTAG and reclaim the GPIOs.
+     * Amiga keyboard map PB4 (KBCLK) to TIM3,CH1 and use its input filter
+     * and edge detector to generate interrupts on clock transitions. */
+    afio->mapr = (AFIO_MAPR_SWJ_CFG_JTAGDISABLE
+                 | AFIO_MAPR_TIM3_REMAP_PARTIAL);
 
     /* All pins in a stable state. */
     gpio_init(gpioa);