Fault is triggered by trying to read LPC_CAN1->IER when the peripheral is powered off. Fixed by checking the power control register before checking the IER register.
While fixing this issue in the various LPC* ports, I noticed a comment
pointing to this mbed forum post which summarizes this bug quite well:
https://mbed.org/forum/bugs-suggestions/topic/4473/
This bug was introduced in the following commit:
2662e105c4
The following code was added to serial_putc() as part of this commit:
uint32_t lsr = obj->uart->LSR;
lsr = lsr;
uint32_t thr = obj->uart->THR;
thr = thr;
As the forum post indicates, this causes the serial_putc() routine to
actually eat an inbound received byte if it exists since reading THR is
really reading the RBR, the Receiver Buffer Register. This code looks
like code that was probably added so that the developer could take a
snapshot of these registers and look at them in the debugger. It
probably got committed in error.
The original code was:
if(LPC_CAN1->IER | LPC_CAN2->IER != 0) {
This would actually be interpreted as:
if(LPC_CAN1->IER | (LPC_CAN2->IER != 0)) {
I simplified it to:
if(LPC_CAN1->IER | LPC_CAN2->IER) {
With the comparison removed, the GCC warning no longer fires since the
user's intent is no longer unclear. However, the end result should be
the same.
These were done to silence GCC warnings and fix potential bugs where
they would never be equal when the enumeration wasn't a 32-bit type.
For example, common/pinmap_common.c used to contain this code:
if (pin == (uint32_t)NC)
I switched it to:
if (pin == (PinName)NC)
I wonder why this casting to uint32_t was done in the first place?
Maybe another supported compiler requires it?
Erik Olieman
Bogdan Marinescu
Joris Aerts
Bogdan Marinescu
Adam Green
Bogdan Marinescu
Emilio Monti