C - Warning [pe069] integer conversion resulted in truncation

Question

I know that this question has been asked several times, anyway I didn't find and answer to my specific case:

IAR Embedded Workbench returs this warning on compiling:

"Warning [pe069] integer conversion resulted in truncation" on the line:

SPI2_Tx(DVC_CTR2,       0x1000);

where DVC_CTR2 is

#define DVC_CTR2                0x0F

and SPI2_Tx definition is

static void SPI2_Tx(uint8_t pAddress, uint8_t pData)

How can I resolve this warning? Thanks in advance!

Possible duplicate of [warning : 'integer conversion results in truncation'](https://stackoverflow.com/questions/9479403/warning-integer-conversion-results-in-truncation) — Jean-François Fabre, Dec 17 '17 at 15:19
@Jean-FrançoisFabre Thank you, so I should go for uint16_t right? — gigapico00, Dec 17 '17 at 15:25
@SaeidYazdani SPI2_Tx is a function of mine, anyway I SOLVED! As Jean-FrançoisFabre said, I just had to change "uint8_t pData" to "uint16_t pData" — gigapico00, Dec 17 '17 at 15:37
Transmitting something over SPI in two chunks might have side effects...it boils down to what the device datasheet says and what is the expected result. — Dumbo, Dec 17 '17 at 15:51

score 4 · Accepted Answer · answered Dec 17 '17 at 15:28

4

This is because you cannot transmit a two-byte value through SPI routine that transmits a single byte.

You should be able to do it with two separate calls:

SPI2_Tx(DVC_CTR2, 0x10);
SPI2_Tx(DVC_CTR2, 0x00);

If you must transmit 16 bits at once, look up a different routine that takes uint16_t.

answered Dec 17 '17 at 15:28

1

that is, of course, if the data is a sequence of bytes. Else, if it depends on endianness, the order of sends must be reversed if little endian – Jean-François Fabre Dec 17 '17 at 15:35

1 Answers1