lpc176x: force minimum usb disconnect time
Fixes GitHub Issue #1499. Resolves USB hang by forcing a minimum USB disconnection time at boot. Signed-off-by: Matt Baker <baker.matt.j@gmail.com>
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@ -18,4 +18,6 @@ int is_enabled_pclock(uint32_t pclk);
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void enable_pclock(uint32_t pclk);
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void enable_pclock(uint32_t pclk);
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void gpio_peripheral(uint32_t gpio, int func, int pullup);
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void gpio_peripheral(uint32_t gpio, int func, int pullup);
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void udelay(uint32_t usecs);
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#endif // internal.h
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#endif // internal.h
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@ -7,6 +7,7 @@
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#include "LPC17xx.h" // NVIC_SystemReset
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#include "LPC17xx.h" // NVIC_SystemReset
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#include "command.h" // DECL_CONSTANT
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#include "command.h" // DECL_CONSTANT
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#include "sched.h" // sched_main
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#include "sched.h" // sched_main
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#include "board/misc.h" // timer_read_time
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DECL_CONSTANT_STR("MCU", "lpc176x");
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DECL_CONSTANT_STR("MCU", "lpc176x");
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@ -66,6 +67,20 @@ command_reset(uint32_t *args)
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}
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}
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DECL_COMMAND_FLAGS(command_reset, HF_IN_SHUTDOWN, "reset");
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DECL_COMMAND_FLAGS(command_reset, HF_IN_SHUTDOWN, "reset");
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// Implement simple early-boot delay mechanism
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void
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udelay(uint32_t usecs)
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{
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if (!(CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk)) {
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CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
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DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
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}
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uint32_t end = timer_read_time() + timer_from_us(usecs);
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while (timer_is_before(timer_read_time(), end))
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;
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}
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// Main entry point
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// Main entry point
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int
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int
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main(void)
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main(void)
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@ -277,6 +277,8 @@ usbserial_init(void)
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gpio_peripheral(GPIO(0, 30), 1, 0);
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gpio_peripheral(GPIO(0, 30), 1, 0);
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gpio_peripheral(GPIO(0, 29), 1, 0);
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gpio_peripheral(GPIO(0, 29), 1, 0);
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gpio_peripheral(GPIO(2, 9), 1, 0);
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gpio_peripheral(GPIO(2, 9), 1, 0);
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// enforce a minimum time bus is disconnected before connecting
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udelay(5000);
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// setup endpoints
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// setup endpoints
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realize_endpoint(EP0OUT, USB_CDC_EP0_SIZE);
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realize_endpoint(EP0OUT, USB_CDC_EP0_SIZE);
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realize_endpoint(EP0IN, USB_CDC_EP0_SIZE);
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realize_endpoint(EP0IN, USB_CDC_EP0_SIZE);
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