/*****************************************************************************
* FUNCTION: ChipReset
*
* RETURNS: N/A
*
* PARAMS:
* N/A
*
*
* NOTES: Performs the necessary SPI operations to cause the MRF24WB0M to reset.
* This function also implements a delay so that it will not return until
* the WiFi device is ready to receive messages again. The delay time will
* vary depending on the amount of code that must be loaded from serial
* flash.
*****************************************************************************/
static void ChipReset(void)
{
UINT16 value;
UINT32 timeoutPeriod;
UINT32 startTickCount;
timeoutPeriod = TICKS_PER_SECOND; /* 1000 ms */
/* needed for Microchip PICTail (chip enable active low) */
WF_SetCE_N(WF_LOW); /* set low to enable regulator */
/* Configure reset pin */
WF_SetRST_N(WF_HIGH);
/* Let SPI lines settle before first SPI transaction */
DelayMs(1);
/* clear the power bit to disable low power mode on the MRF24WB0M */
Write16BitWFRegister(WF_PSPOLL_H_REG, 0x0000);
/* Set HOST_RESET bit in register to put device in reset */
Write16BitWFRegister(WF_HOST_RESET_REG, Read16BitWFRegister(WF_HOST_RESET_REG) | WF_HOST_RESET_MASK);
/* Clear HOST_RESET bit in register to take device out of reset */
Write16BitWFRegister(WF_HOST_RESET_REG, Read16BitWFRegister(WF_HOST_RESET_REG) & ~WF_HOST_RESET_MASK);
/* after reset is started poll register to determine when HW reset has completed */
startTickCount = (UINT32)TickGet();
do
{
Write16BitWFRegister(WF_INDEX_ADDR_REG, WF_HW_STATUS_REG);
value = Read16BitWFRegister(WF_INDEX_DATA_REG);
if (TickGet() - startTickCount >= timeoutPeriod)
{
WF_ASSERT(FALSE);
}
} while ( (value & WF_HW_STATUS_NOT_IN_RESET_MASK) == 0);
/* if SPI not connected will read all 1's */
WF_ASSERT(value != 0xffff);
/* now that chip has come out of HW reset, poll the FIFO byte count register */
/* which will be set to a non-zero value when the MRF24WB0M initialization is */
/* complete. */
startTickCount = (UINT32)TickGet();
do
{
value = Read16BitWFRegister(WF_HOST_WFIFO_BCNT0_REG);
if (TickGet() - startTickCount >= timeoutPeriod)
{
WF_ASSERT(FALSE);
}
} while (value == 0);
}
/*****************************************************************************
* FUNCTION: WFHardwareInit
*
* RETURNS: error code
*
* PARAMS: None
*
* NOTES: Initializes CPU Host hardware interfaces (SPI, External Interrupt).
* Also resets the MRF24W.
*****************************************************************************/
void WFHardwareInit(void)
{
UINT8 mask8;
UINT16 mask16;
g_MgmtReadMsgReady = FALSE;
g_ExIntNeedsServicing = FALSE;
RawMoveState.rawInterrupt = 0;
RawMoveState.waitingForRawMoveCompleteInterrupt = FALSE; /* not waiting for RAW move complete */
/* initialize the SPI interface */
WF_SpiInit();
#if defined(__Digilent_Build__)
WF_SetRST_N(WF_LOW); // put module into reset; should already be there.
// we have taken out the next 3 lines as MarkW says we do not need to toggle HIB to competely reset the part.
// WF_SetCE_N(WF_HIGH); // disable module, turn off regulators
// DelayMs(200); // 200ms to allow decoupling caps to discharge, between the 70uF in the MRF , this can take some time.
// WF_SetCE_N(WF_LOW); // enable module, turn on regulators; careful this has an inrush that can drag the Power supply below min. if the MRF is not decoupled well enough.
DelayMs(2); // Spec says at least 1ms to let the regulators settle, leave this here to ensure timing from board powerup.
WF_SetRST_N(WF_HIGH); // take module out of of reset
DelayMs(5); // Per MarkW’s email, leave 5ms here before accessing the SPI port
#else
/* Toggle the module into and then out of hibernate */
WF_SetCE_N(WF_HIGH); /* disable module */
WF_SetCE_N(WF_LOW); /* enable module */
/* Toggle the module into and out of reset */
WF_SetRST_N(WF_LOW); // put module into reset
WF_SetRST_N(WF_HIGH); // take module out of of reset
#endif
/* Silicon work-around -- needed for A1 silicon to initialize PLL values correctly */
ResetPll();
/* Soft reset the MRF24W (using SPI bus to write/read MRF24W registers */
ChipReset();
/* disable the interrupts gated by the 16-bit host int register */
HostInterrupt2RegInit(WF_HOST_2_INT_MASK_ALL_INT, (UINT16)WF_INT_DISABLE);
/* disable the interrupts gated the by main 8-bit host int register */
HostInterruptRegInit(WF_HOST_INT_MASK_ALL_INT, WF_INT_DISABLE);
/* Initialize the External Interrupt for the MRF24W allowing the MRF24W to interrupt */
/* the Host from this point forward. */
WF_EintInit();
WF_EintEnable();
/* enable the following MRF24W interrupts in the INT1 8-bit register */
mask8 = (WF_HOST_INT_MASK_FIFO_1_THRESHOLD | /* Mgmt Rx Msg interrupt */
WF_HOST_INT_MASK_FIFO_0_THRESHOLD | /* Data Rx Msg interrupt */
WF_HOST_INT_MASK_RAW_0_INT_0 | /* RAW0 Move Complete (Data Rx) interrupt */
WF_HOST_INT_MASK_RAW_1_INT_0 | /* RAW1 Move Complete (Data Tx) interrupt */
WF_HOST_INT_MASK_INT2); /* Interrupt 2 interrupt */
HostInterruptRegInit(mask8, WF_INT_ENABLE);
/* enable the following MRF24W interrupts in the INT2 16-bit register */
mask16 = (WF_HOST_INT_MASK_RAW_2_INT_0 | /* RAW2 Move Complete (Mgmt Rx) interrupt */
WF_HOST_INT_MASK_RAW_3_INT_0 | /* RAW3 Move Complete (Mgmt Tx) interrupt */
WF_HOST_INT_MASK_RAW_4_INT_0 | /* RAW4 Move Complete (Scratch) interrupt */
WF_HOST_INT_MASK_RAW_5_INT_0 | /* RAW5 Move Complete (Scratch) interrupt */
WF_HOST_INT_MASK_MAIL_BOX_0_WRT);
HostInterrupt2RegInit(mask16, WF_INT_ENABLE);
/* Disable PS-Poll mode */
WFConfigureLowPowerMode(WF_LOW_POWER_MODE_OFF);
}