//---------------------------------------------------------------------------
// Check to see if there is a short on the 1-Wire bus. Used to stop
// communication with the DS2490 while the short is in effect to not
// overrun the buffers.
//
// '*present' - flag set (1) if device presence detected
// '*vpp' - flag set (1) if Vpp programming voltage detected
//
// Returns: TRUE - DS2490 1-Wire is NOT shorted
// FALSE - Could not detect DS2490 or 1-Wire shorted
//
SMALLINT DS2490ShortCheck(usb_dev_handle *hDevice, SMALLINT *present, SMALLINT *vpp)
{
STATUS_PACKET status;
uchar nResultRegisters;
uchar i;
// get the result registers (if any)
if (!DS2490GetStatus(hDevice, &status, &nResultRegisters))
return FALSE;
// get vpp present flag
*vpp = ((status.StatusFlags & STATUSFLAGS_12VP) != 0);
// Check for short
if(status.CommBufferStatus != 0)
{
return FALSE;
}
else
{
// check for short
for (i = 0; i < nResultRegisters; i++)
{
// check for SH bit (0x02), ignore 0xA5
if (status.CommResultCodes[i] & COMMCMDERRORRESULT_SH)
{
// short detected
return FALSE;
}
}
}
// check for No 1-Wire device condition
*present = TRUE;
// loop through result registers
for (i = 0; i < nResultRegisters; i++)
{
// only check for error conditions when the condition is not a ONEWIREDEVICEDETECT
if (status.CommResultCodes[i] != ONEWIREDEVICEDETECT)
{
// check for NRS bit (0x01)
if (status.CommResultCodes[i] & COMMCMDERRORRESULT_NRS)
{
// empty bus detected
*present = FALSE;
}
}
}
return TRUE;
}
//---------------------------------------------------------------------------
// Stop any on-going pulses
//
// Returns: TRUE - pulse stopped
// FALSE - Could not stop pulse
//
SMALLINT DS2490HaltPulse(usb_dev_handle *hDevice)
{
STATUS_PACKET status;
uchar nResultRegisters;
SETUP_PACKET setup;
SMALLINT ret;
long limit;
// set a time limit
limit = msGettick() + 300;
// loop until confirm pulse has ended or timeout
do
{
// HalExecWhenIdle, Resume Execution to stop an infinite pulse
// HalExecWhenIdle
setup.RequestTypeReservedBits = 0x40;
setup.Request = CONTROL_CMD;
setup.Value = CTL_HALT_EXE_IDLE;
setup.Index = 0x00;
setup.Length = 0x00;
setup.DataOut = FALSE;
// call the libusb driver
ret = usb_control_msg(hDevice,
setup.RequestTypeReservedBits,
setup.Request,
setup.Value,
setup.Index,
NULL,
setup.Length,
TIMEOUT_LIBUSB);
if (ret < 0)
{
// failure
break;
}
// Resume Execution
setup.RequestTypeReservedBits = 0x40;
setup.Request = CONTROL_CMD;
setup.Value = CTL_RESUME_EXE;
setup.Index = 0x00;
setup.Length = 0x00;
setup.DataOut = FALSE;
// call the libusb driver
ret = usb_control_msg(hDevice,
setup.RequestTypeReservedBits,
setup.Request,
setup.Value,
setup.Index,
NULL,
setup.Length,
TIMEOUT_LIBUSB);
if (ret < 0)
{
// failure
break;
}
// read the status to see if the pulse has been stopped
if (!DS2490GetStatus(hDevice, &status, &nResultRegisters))
{
// failure
break;
}
else
{
// check the SPU flag
if ((status.StatusFlags & STATUSFLAGS_SPUA) == 0)
{
// success
// disable both pulse types
setup.RequestTypeReservedBits = 0x40;
setup.Request = MODE_CMD;
setup.Value = MOD_PULSE_EN;
setup.Index = 0;
setup.Length = 0x00;
setup.DataOut = FALSE;
// call the libusb driver
ret = usb_control_msg(hDevice,
setup.RequestTypeReservedBits,
setup.Request,
setup.Value,
setup.Index,
NULL,
setup.Length,
TIMEOUT_LIBUSB);
return TRUE;
}
}
}
while (limit > msGettick());
return FALSE;
}
//--------------------------------------------------------------------------
// The 'owNext' function does a general search. This function
// continues from the previos search state. The search state
// can be reset by using the 'owFirst' function.
// This function contains one parameter 'alarm_only'.
// When 'alarm_only' is TRUE (1) the find alarm command
// 0xEC is sent instead of the normal search command 0xF0.
// Using the find alarm command 0xEC will limit the search to only
// 1-Wire devices that are in an 'alarm' state.
//
// 'portnum' - number 0 to MAX_PORTNUM-1. This number is provided to
// indicate the symbolic port number.
// 'do_reset' - TRUE (1) perform reset before search, FALSE (0) do not
// perform reset before search.
// 'alarm_only' - TRUE (1) the find alarm command 0xEC is
// sent instead of the normal search command 0xF0
//
// Returns: TRUE (1) : when a 1-Wire device was found and it's
// Serial Number placed in the global SerialNum[portnum]
// FALSE (0): when no new device was found. Either the
// last search was the last device or there
// are no devices on the 1-Wire Net.
//
SMALLINT owNext(int portnum, SMALLINT do_reset, SMALLINT alarm_only)
{
SETUP_PACKET setup;
short rt=FALSE,i,ResetSearch=FALSE;
BYTE rom_buf[16];
BYTE ret_buf[16];
WORD buf_len;
uchar lastcrc8;
WORD nBytes = 8;
ULONG nOutput = 0;
long limit;
STATUS_PACKET status;
BYTE nResult;
// if the last call was the last one
if (LastDevice[portnum])
{
// reset the search
LastDiscrepancy[portnum] = 0;
LastDevice[portnum] = FALSE;
LastFamilyDiscrepancy[portnum] = 0;
return FALSE;
}
// check if reset first is requested
if (do_reset)
{
// reset the 1-wire
// extra reset if last part was a DS1994/DS2404 (due to alarm)
if ((SerialNum[portnum][0] & 0x7F) == 0x04)
owTouchReset(portnum);
// if there are no parts on 1-wire, return FALSE
if (!owTouchReset(portnum))
{
// reset the search
LastDiscrepancy[portnum] = 0;
LastFamilyDiscrepancy[portnum] = 0;
OWERROR(OWERROR_NO_DEVICES_ON_NET);
return FALSE;
}
}
// build the rom number to put to the USB chip
for (i = 0; i < 8; i++)
rom_buf[i] = SerialNum[portnum][i];
// take into account LastDiscrepancy
if (LastDiscrepancy[portnum] != 0xFF)
{
if (LastDiscrepancy[portnum] > 0)
bitacc(WRITE_FUNCTION,1,(short)(LastDiscrepancy[portnum] - 1),rom_buf);
for (i = LastDiscrepancy[portnum]; i < 64; i++)
bitacc(WRITE_FUNCTION,0,i,rom_buf);
}
// put the ROM ID in EP2
nBytes = 8;
if (!DS2490Write(usbhnd[portnum], rom_buf, &nBytes))
{
AdapterRecover(portnum);
return FALSE;
}
// setup for search command call
setup.RequestTypeReservedBits = 0x40;
setup.Request = COMM_CMD;
setup.Value = COMM_SEARCH_ACCESS | COMM_IM | COMM_SM | COMM_F | COMM_RTS;
// the number of devices to read (1) with the search command
setup.Index = 0x0100 | (((alarm_only) ? 0xEC : 0xF0) & 0x00FF);
setup.Length = 0;
setup.DataOut = FALSE;
// call the driver
if (!DeviceIoControl(usbhnd[portnum],
DS2490_IOCTL_VENDOR,
&setup,
sizeof(SETUP_PACKET),
NULL,
0,
&nOutput,
NULL))
{
// failure
AdapterRecover(portnum);
return FALSE;
}
// set a time limit
limit = msGettick() + 200;
// loop to wait on EP3 ready (device will go idle)
do
{
// read the status to see if the pulse has been stopped
if (!DS2490GetStatus(usbhnd[portnum], &status, &nResult))
{
// failure
break;
}
else
{
// look for any fail conditions
for (i = 0; i < nResult; i++)
{
// only check for error conditions when the condition is not a ONEWIREDEVICEDETECT
if (status.CommResultCodes[i] != ONEWIREDEVICEDETECT)
{
// failure
break;
}
}
}
}
while (((status.StatusFlags & STATUSFLAGS_IDLE) == 0) &&
(limit > msGettick()));
// check results of the waite for idel
if ((status.StatusFlags & STATUSFLAGS_IDLE) == 0)
{
AdapterRecover(portnum);
return FALSE;
}
// check for data
if (status.ReadBufferStatus > 0)
{
// read the load
buf_len = 16;
if(!DS2490Read(usbhnd[portnum], ret_buf, &buf_len))
{
AdapterRecover(portnum);
return FALSE;
}
// success, get rom and desrepancy
LastDevice[portnum] = (buf_len == 8);
// extract the ROM (and check crc)
setcrc8(portnum,0);
for (i = 0; i < 8; i++)
{
SerialNum[portnum][i] = ret_buf[i];
lastcrc8 = docrc8(portnum,ret_buf[i]);
}
// crc OK and family code is not 0
if (!lastcrc8 && SerialNum[portnum][0])
{
// loop through the descrepancy to get the pointers
for (i = 0; i < 64; i++)
{
// if descrepancy
if (bitacc(READ_FUNCTION,0,i,&ret_buf[8]) &&
(bitacc(READ_FUNCTION,0,i,&ret_buf[0]) == 0))
{
LastDiscrepancy[portnum] = i + 1;
}
}
rt = TRUE;
}
else
{
ResetSearch = TRUE;
rt = FALSE;
}
}
// check if need to reset search
if (ResetSearch)
{
LastDiscrepancy[portnum] = 0xFF;
LastDevice[portnum] = FALSE;
for (i = 0; i < 8; i++)
SerialNum[portnum][i] = 0;
}
return rt;
}
