Error when using c++ with TWI

RE: Error when using c++ with TWI

MartinBL — Thu, 08 Mar 2018 09:46:24 GMT

Hi,

The SDK team confirmed that this is indeed finally fixed in SDK 15.

RE: Error when using c++ with TWI

Jeffrey Haynes — Thu, 01 Mar 2018 01:54:37 GMT

Can Nordic please make this change in the SDK? I've had to make it several times now by hand. Thanks.

RE: Error when using c++ with TWI

MartinBL — Wed, 04 Oct 2017 10:44:37 GMT

Hi Bojan. The SDK team agreed with your thoughts, and the issue is added on the to-do list. Though it might not be included in the SDK before a couple of releases into the future.

RE: Error when using c++ with TWI

Bojan Potocnik — Mon, 02 Oct 2017 11:42:52 GMT

Martin, may I ask why is this not changed in the SDK itself (using SDK v14.0.0)? Considering the fact that the union reg in nrf_drv_uart_t struct typedef (file nrf_drv_twi.h) is always defined with at least two members (p_regs and p_twim or p_regs and p_twi) and p_regs pointer is always present, why don't you just do:

.reg = { .p_regs = NRF_DRV_TWI_PERIPHERAL(id) }, \

if you are already casting NRF_DRV_TWI_PERIPHERAL(id) macro to void *? Otherwise, there shall be:

#if defined(TWIM_IN_USE)
    .reg = { .p_twim = (NRF_TWIM_Type *) NRF_DRV_TWI_PERIPHERAL(id) }, \
#elif defined(TWI_IN_USE)
    .reg = { .p_twi = (NRF_TWI_Type *) NRF_DRV_TWI_PERIPHERAL(id) }, \
#endif

The same goes for NRF_DRV_UART_INSTANCE(id) which also throws -fpermissive error using C++. Is solution with .p_regs not used because of missing initializer warning?

RE: Error when using c++ with TWI

schef — Tue, 29 Aug 2017 06:06:04 GMT

Yes i have solved it.

RE: Error when using c++ with TWI

MartinBL — Thu, 24 Aug 2017 08:43:31 GMT

So you solved it?

RE: Error when using c++ with TWI

schef — Thu, 10 Aug 2017 15:36:37 GMT

I'm sorry. The M was missing.

RE: Error when using c++ with TWI

schef — Thu, 10 Aug 2017 15:33:55 GMT

In sdk14 i get

In file included from ../../../main.cpp:56:0:
../../../../../../components/drivers_nrf/twi_master/nrf_drv_twi.h:173:1: error: 'nrf_drv_twi_t::<unnamed union>' has no non-static data member named 'p_twi'
 }
 ^
../../../main.cpp:71:36: note: in expansion of macro 'NRF_DRV_TWI_INSTANCE'
 static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);

RE: Error when using c++ with TWI

All4here — Tue, 02 Aug 2016 19:56:43 GMT

i found solution too.

just change with this

.reg = { .p_twi = (NRF_TWI_Type*)NRF_DRV_TWI_PERIPHERAL(id) },         \

RE: Error when using c++ with TWI

MartinBL — Tue, 14 Jun 2016 12:44:35 GMT

I just realized that in your error it says NRF_TWIM_Type so I guess you are using EasyDMA. Hence the code above should probably say

.reg          = {.p_twim = NRF_DRV_TWI_PERIPHERAL(id)},         \

Although if you still get the same error then obviously it wasn't the problem.

I googled a bit and the error seems related to converting pointers and types back and forth, so maybe it is worth a shot to explicitly cast NRF_DRV_TWI_PERIPHERAL(id) to a NRF_TWIM_Type like this:

.reg          = {.p_twim = (NRF_TWIM_Type*)NRF_DRV_TWI_PERIPHERAL(id)},         \

I'm unable to test it here right now. If that doesn't work then I'm out of ideas I'm afraid. I talked to the developer of the driver and he didn't have any further suggestions either.

RE: Error when using c++ with TWI

Tony — Mon, 13 Jun 2016 15:53:51 GMT

Thanks Martin for your reply. I tried that and still am getting same error. Any other workarounds ? Thanks much !

RE: Error when using c++ with TWI

MartinBL — Mon, 13 Jun 2016 11:22:50 GMT

Hi,

In this line in the header file:

.reg          = {NRF_DRV_TWI_PERIPHERAL(id)},       \

we assign things to a union, but without specifying which particular element in the union. Some compilers might not like that. Can you please try to change

#define NRF_DRV_TWI_INSTANCE(id)                        \
{                                                       \
    .reg          = {NRF_DRV_TWI_PERIPHERAL(id)},       \
    .drv_inst_idx = CONCAT_3(TWI, id, _INSTANCE_INDEX), \
    .use_easy_dma = CONCAT_3(TWI, id, _USE_EASY_DMA)    \
}

#define NRF_DRV_TWI_INSTANCE(id)                        \
{                                                       \
    .reg          = {.p_twi = NRF_DRV_TWI_PERIPHERAL(id)},         \
    .drv_inst_idx = CONCAT_3(TWI, id, _INSTANCE_INDEX), \
    .use_easy_dma = CONCAT_3(TWI, id, _USE_EASY_DMA)    \
}

in nrf_drw_twi.h?