/******************************************************************************
Function:
void putUSBUSART(char *data, BYTE length)
Summary:
putUSBUSART writes an array of data to the USB. Use this version, is
capable of transfering 0x00 (what is typically a NULL character in any of
the string transfer functions).
Description:
putUSBUSART writes an array of data to the USB. Use this version, is
capable of transfering 0x00 (what is typically a NULL character in any of
the string transfer functions).
Typical Usage:
<code>
if(USBUSARTIsTxTrfReady())
{
char data[] = {0x00, 0x01, 0x02, 0x03, 0x04};
putUSBUSART(data,5);
}
</code>
The transfer mechanism for device-to-host(put) is more flexible than
host-to-device(get). It can handle a string of data larger than the
maximum size of bulk IN endpoint. A state machine is used to transfer a
\long string of data over multiple USB transactions. CDCTxService()
must be called periodically to keep sending blocks of data to the host.
Conditions:
USBUSARTIsTxTrfReady() must return TRUE. This indicates that the last
transfer is complete and is ready to receive a new block of data. The
string of characters pointed to by 'data' must equal to or smaller than
255 BYTEs.
Input:
char *data - pointer to a RAM array of data to be transfered to the host
BYTE length - the number of bytes to be transfered (must be less than 255).
*****************************************************************************/
void putUSBUSART(char *data, BYTE length)
{
/*
* User should have checked that cdc_trf_state is in CDC_TX_READY state
* before calling this function.
* As a safety precaution, this fuction checks the state one more time
* to make sure it does not override any pending transactions.
*
* Currently it just quits the routine without reporting any errors back
* to the user.
*
* Bottomline: User MUST make sure that USBUSARTIsTxTrfReady()==1
* before calling this function!
* Example:
* if(USBUSARTIsTxTrfReady())
* putUSBUSART(pData, Length);
*
* IMPORTANT: Never use the following blocking while loop to wait:
* while(!USBUSARTIsTxTrfReady())
* putUSBUSART(pData, Length);
*
* The whole firmware framework is written based on cooperative
* multi-tasking and a blocking code is not acceptable.
* Use a state machine instead.
*/
USBMaskInterrupts();
if(cdc_trf_state == CDC_TX_READY)
{
mUSBUSARTTxRam((BYTE*)data, length); // See cdc.h
}
USBUnmaskInterrupts();
}//end putUSBUSART
void putcUSBUSART(char data)
{
USBMaskInterrupts();
if(cdc_trf_state == CDC_TX_READY)
{
mUSBUSARTTxRam((BYTE*)&data, 1); // See cdc.h
}
USBUnmaskInterrupts();
}
void putsUSBUSART(char *data)
{
BYTE len;
char *pData;
/*
* User should have checked that cdc_trf_state is in CDC_TX_READY state
* before calling this function.
* As a safety precaution, this fuction checks the state one more time
* to make sure it does not override any pending transactions.
*
* Currently it just quits the routine without reporting any errors back
* to the user.
*
* Bottomline: User MUST make sure that USBUSARTIsTxTrfReady()==1
* before calling this function!
* Example:
* if(USBUSARTIsTxTrfReady())
* putsUSBUSART(pData, Length);
*
* IMPORTANT: Never use the following blocking while loop to wait:
* while(!USBUSARTIsTxTrfReady())
* putsUSBUSART(pData);
*
* The whole firmware framework is written based on cooperative
* multi-tasking and a blocking code is not acceptable.
* Use a state machine instead.
*/
USBMaskInterrupts();
if(cdc_trf_state != CDC_TX_READY)
{
USBUnmaskInterrupts();
return;
}
/*
* While loop counts the number of BYTEs to send including the
* null character.
*/
len = 0;
pData = data;
do
{
len++;
if(len == 255) break; // Break loop once max len is reached.
}while(*pData++);
/*
* Second piece of information (length of data to send) is ready.
* Call mUSBUSARTTxRam to setup the transfer.
* The actual transfer process will be handled by CDCTxService(),
* which should be called once per Main Program loop.
*/
mUSBUSARTTxRam((BYTE*)data, len); // See cdc.h
USBUnmaskInterrupts();
}//end putsUSBUSART
