Texas Instruments MSC1210 manual SFR Definitions

SFR Definitions

DPL0/DPH0 (Data Pointer 0 Low/High, Addresses 82H/83H): The SFRs DPL0 and DPH0 work together to represent a 16-bit value called Data Pointer

0.The data pointer is used in operations regarding external RAM and some

instructions involving code memory. It can represent values from 0000H to FFFFH (0 through 65,535 decimal) because it is an unsigned 2-byte integer value,

Note:

DPTR is really DPH0 and DPL0 taken together as a 16-bit value. In reality, DPTR must almost always be dealt with one byte at a time. For example, to push DPTR onto the stack, first push DPL0 and then DPH0. It is not possible to simply push DPTR onto the stack as a single value. Additionally, there is an instruction to increment DPTR. When this instruction is executed, the two bytes are operated upon as a 16-bit value. However, there is no instruction which decrements DPTR. If it is necessary to decrement the value of DPTR, special code must be written to do so. DPTR is a useful storage location for occasional 16-bit values that are being manipulated by your program—especially if those values need to be incremented frequently.

DPL1/DPH1 (Data Pointer 1 Low/High, Addresses 84H/85H): These two SFRs work together to form a 16-bit value called Data Pointer 1. Its purpose and function is the same as DPL0/DPH0 just described. The existence of two distinct data point- ers allows a program to quickly copy data from one area of memory to another.

DPS (Data Pointer Select, Address 86H): Bit 0 of this SFR determines whether instructions that refer to DPTR will use Data Pointer 0 or Data Pointer 1. If bit 0 is clear, Data Pointer 0 will be used (DPH0/DPL0). If bit 1 is set, Data Pointer 1 will be used (DPH1/DPL1).

PCON (Power Control, Address 87H): This SFR is used to control the MSC1210 CPU power control modes. Certain operation modes allow the MSC1210 to go into a type of sleep mode that requires much less power. These modes of operation are controlled through PCON. Additionally, one of the bits in PCON is used to double the effective baud rate of the MSC1210 primary serial port. Do not confuse it with PDCON, which controls peripheral power-down.

TCON (Timer Control, Address 88H, Bit-Addressable): This SFR is used to configure and modify the way in which the two timers of the 8052 operate. This SFR controls whether each of the two timers is running or stopped, and contains a flag to indicate whether each timer has overflowed. Additionally, some non-timer related bits are located in the TCON SFR. These bits are used to configure the way in which the external interrupts are activated and also con- tain the external interrupt flags that are set when an external interrupt has oc- curred.

T2CON (Timer Control 2, Address C8H, Bit-Addressable): This SFR is used to configure and control the way in which timer 2 operates. This SFR is only available on 8052s, and not on 8051s.

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