Texas Instruments MSC1210 manual GCL/GCM/GCH Gain Low/Middle/High Byte, Addresses D4H/D5H/D6H

SFR Definitions

SCON1 (Serial Control 1, Address C0H, Bit-Addressable): This SFR is used to configure the behavior of the MSC1210 secondary onboard serial port. SCON1 controls the baud rate of the serial port, whether the serial port is acti- vated to receive data, and also contains flags that are set when a byte is suc- cessfully sent or received.

SBUF1 (Serial Buffer 1, Address C1H): This SFR is used to send and receive data via the secondary onboard serial port. Any value written to SBUF1 will be sent out the serial port TXD1 pin. Likewise, any value that the MSC1210 receives via the serial port RXD1 pin will be delivered to the user program via SBUF1. In other words, SBUF1 serves as the output port when written to, and as an input port when read from.

EWU (Enable Wake−up, Address C6 H): The EWU SFR controls under what

conditions the MSC1210 will wake up from idle mode: external 1 interrupt, ex- ternal 0 interrupt, and watchdog interrupt. Idle wakeup from Auxint is con- trolled via EAI bit of EICON SFR.

PSW (Program Status Word, Address D0H, Bit-Addressable): This SFR is used to store a number of important bits that are set and cleared by instruc- tions. The PSW SFR contains the carry flag, the auxiliary carry flag, the over- flow flag, and the parity flag. Additionally, the PSW SFR contains the register bank select flags that are used to select which of the R register banks are cur- rently selected.

Note:

When writing an interrupt handler routine, it is a very good idea to always save the PSW SFR on the stack and restore it when the interrupt is complete. Many instructions modify the bits of the PSW. If the interrupt routine does not ensure that the PSW is the same upon exit as it was upon entry, the program is bound to behave rather erratically and unpredictably, and it will be tricky to debug because the behavior may not make any sense.

OCL/OCM/OCH (Offset Calibration Low/Middle/High Byte, Addresses

D1H/D2H/D3H): These three SFRs make up a 24-bit value that sets the ADC offset calibration.

GCL/GCM/GCH (Gain Low/Middle/High Byte, Addresses D4H/D5H/D6H):

These three SFRs make up a 24-bit value that sets ADC gain calibration.

ADMUX (ADC Multiplexer Register, Address D7H): This SFR selects the positive input for the ADC and/or selects the temperature sensor option.

EICON (Enable Interrupt Control, Address D8H, Bit-Addressable): This SFR controls whether or not the additional interrupts provided by the MSC1210 will cause an interrupt to occur when their corresponding conditions are en- abled.

ADRESL/ADRESM/ADRESH (ADC Conversion Results, Addresses

D9H/DAH/DBH): These three SFRs make up a 24−bit value which holds the re- sults of an ADC conversion.

Special Function Registers (SFRs) 3-11