---
title: HwProgramMCR
framework: serialdriverkit
role: symbol
role_heading: Instance Method
path: serialdriverkit/iouserserial/hwprogrammcr
---

# HwProgramMCR

Configure the setings for the device’s modem control register (MCR).

## Declaration

```occ
virtual kern_return_t HwProgramMCR(bool dtr, bool rts);
```

## Parameters

- `dtr`: A Boolean value indicating whether to set or clear the data-terminal-ready bit. If the value is YES, set the bit; otherwise, clear it.
- `rts`: A Boolean value indicating whether to set or clear the request-to-send bit. If the value is YES, set the bit; otherwise, clear it.

## Return Value

Return Value kIOReturnSuccess on success, or another value if an error occurs. See Error Codes.

## Discussion

Discussion Override this method and use it to program your hardware with the specified information.

## See Also

### Programming the Modem

- [HwGetModemStatus](serialdriverkit/iouserserial/hwgetmodemstatus.md)
- [SetModemStatus](serialdriverkit/iouserserial/setmodemstatus.md)
- [HwResetFIFO](serialdriverkit/iouserserial/hwresetfifo.md)
- [HwSendBreak](serialdriverkit/iouserserial/hwsendbreak.md)
- [HwProgramBaudRate](serialdriverkit/iouserserial/hwprogrambaudrate.md)
- [HwProgramLatencyTimer](serialdriverkit/iouserserial/hwprogramlatencytimer.md)
- [HwProgramUART](serialdriverkit/iouserserial/hwprogramuart.md)
- [Hardware Constants](serialdriverkit/hardware-constants.md)