Peripheral Simulation

For Texas Instruments MSC1212Y3 — Port 0

Simulation support for this peripheral or feature is comprised of:

• Dialog boxes which display and allow you to change peripheral configuration.
• VTREGs (Virtual Target Registers) which support I/O with the peripheral.

These simulation capabilities are described below.

Parallel Port 0 Dialog

This dialog displays the SFR and pins of Port 0. The I/O pins of this port may be configured to operate in one of several configurations by changing the values of the data direction registers (P0DDRH and P0DDRL). The following configuration values are possible.

Configuration    P0DDRH   P0DDRL
--------------------------------
Standard 8051       0        0
CMOS Output         0        1
Open-Drain Output   1        0
Input               1        1
--------------------------------

• P0 represents the P0 SFR. The HEX value and value of each bit is displayed and may be changed from this dialog.
• P0DDRH represents the P0DDRH SFR (the high-order bit of the data direction register). The HEX value and value of each bit is displayed and may be changed from this dialog.
• P0DDRL represents the P0DDRL SFR (the low-order bit of the data direction register). The HEX value and value of each bit is displayed and may be changed from this dialog.
• Pins represents the states of the pins on the simulated MCU. When used as outputs, these have the same value as the P0 SFR. When used as inputs you may set the level of the input pin to high (1) or low (0).

You may use the PORTx VTREGs to change the state of the input pins on the simulator command line or in user or signal functions.

PORTx VTREG
Data Type: unsigned char

The PORTx VTREGs represent the I/O pins of the simulated MCU for Port 0, Port 1, and so on. PORT0 represents Port 0, PORT1 represents Port 1, etc. You may read PORTx to determine the state of the output pins of that port. For example, in the command window, you may type,

PORT0

to obtain value corresponding to the set pins of Port 0. You may also change the input values of port pins by changing the value of the VTREG. For example,

PORT1=0xF0

sets the upper four port pins of Port 1 to a value of 1 and the lower 4 port pins to a value of 0. You may use the bitwise operators AND(&), OR(|) and XOR(^) to change individual bits of the PORTx VTREGs. For example:

PORT1 |=  0x01;  /* Set P1.0 Pin */
PORT3 &= ~0x02;  /* Clr P3.1 Pin */
PORT1 ^=  0x80;  /* Toggle P1.7 Pin */