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fw/boot/boot.c (boot_loader): removed description of IDBG-specific power
sensing.
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parent
efdacaf589
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@ -186,30 +186,6 @@ static void boot_loader(void)
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printk("%s #%u\n", build_date, build_number);
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printk("%s #%u\n", build_date, build_number);
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/*
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* Very weakly pull SDA down and disable all pull-ups.
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*
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* We use SDA as a system power presence detector. When I2C is idle,
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* SDA is kept high. This is accomplished with pull-ups in the system.
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* We can therefore detect if IO_3V3 is any good by checking whether
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* SDA is high.
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*
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* This should work even without our own pull-down. However, when the
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* IDBG board is operating standalone (or, generally, if SDA isn't
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* connected), SDA would float. We therefore have to pull it down a
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* little.
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*/
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/*
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* Ben variant:
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*
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* We use exactly the same logic as on GTA01/02, but with different
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* signals. P0_1 (I2C_SDA_PULL) and P0_2 (I2C_SDA) both connect to
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* +V3.3, with a 1 kOhm resistor on P0_1. If the Ben is not powered, we
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* can therefore pull +V3.3 to GND, and detect this condition. As on
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* the GTA01/02, once the system is powered up, IDBG exits this loop.
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*/
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PLATFORM_SETUP;
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PLATFORM_SETUP;
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dfu_init();
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dfu_init();
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