From the ARMv7-M ARM section B3.5.3:
Where there is an overlap between two regions, the register with
the highest region number takes priority.
We want to make sure the mpu_noexec_ram region has the lowest
priority to allow the mpu_stack_guard region to overwrite the first N
bytes of it.
This change fixes using mpu_noexec_ram and mpu_stack_guard together.
cc2538 implements 4 sleep modes.
In the lightest mode (3) any interrupt source can wake up the CPU.
In mode 2, only RTT, GPIO or USB may wake the CPU.
In mode 1 only RTT and GPIO can wake the CPU.
In mode 0 only GPIO can wake the CPU.
In mode 0 and 1 the lower 16k RAM are lost. This is a problem since those
are usually used by RIOT.
The linkerscripts in cc2538/ldscripts take different approaches towards that.
Some only use the upper 16k and leave the other half to be managed by the
application.
`cc2538sf53.ld` which is used by `openmote-b` uses the entire RAM starting
at the lower half, so it will not be able to wake up from those modes.
A quick fix to test those modes with `tests/periph_pm` would be
--- a/cpu/cc2538/ldscripts/cc2538sf53.ld
+++ b/cpu/cc2538/ldscripts/cc2538sf53.ld
@@ -21,7 +21,7 @@ MEMORY
{
rom (rx) : ORIGIN = 0x00200000, LENGTH = 512K - 44
cca : ORIGIN = 0x0027ffd4, LENGTH = 44
- ram (w!rx) : ORIGIN = 0x20000000, LENGTH = 32K
+ ram (w!rx) : ORIGIN = 0x20004000, LENGTH = 16K
}
If memarray data is not initialized to 0 (for instance during a
re-init). The last element of the array is not properly cleared thus
leading to returning an invalid pointer when everything is allocated.
This removes the configuration parameters for mrf24j40 and enc28j60
drivers, which were present in the boards's Makefile.dep. There is
already documentation regarding how to correctly configure these devices
for the board.
We have to read the DR for every byte that we write.
Just reading DR while SPI is busy in a loop can lead to bytes being
left in the fifo, corrupting subsequent reads.
`netopt_state_t` is an enumeration type which is not necessarily 1 byte. If `uint8_t` is used, the cast `*((const netopt_state_t*) val` in `sx127x_netdev::_set`tries to read the real size, which can be more than the given length of 1 byte. Therefore, `netstat_opt_t` has to be used instead of `uint8_t`