Peripheral Simulation
For STMicroelectronics STR712FR1 — UART 3
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.
UART 3 Dialog
Serial Input for UARTx VTREG
Data Type: unsigned short
The SxIN VTREG represents the serial input of the simulated
microcontroller. Values you assign to SxIN are input to the serial
channel 0, 1, 2, and so on. You may assign input using the command
window. For example,
S0IN='A'
causes the simulated microcontroller serial input 0 to receive the
ASCII character A. If you want to use the SxIN VRTEG to simulate
reception of multiple characters, you must be sure to delay for at
least one character time between successive assignments to SxIN. This
may be done using a signal function. For example:
signal void send_cat (void) {
swatch(0.01); /* Wait 1/100 seconds */
S0IN='C'; /* Send a C */
swatch(0.01);
S0IN='A';
swatch(0.01);
S0IN='T';
}
You may use the SxIN VTREG to input data (5-9 bits), parity, frame
error and break condition. SxIN Format (16-bit Register)
- Bits 0-8: Data (5, 6, 7, 8 or 9 bit)
- Bit 9: Parity bit Value
- Bit 10: Parity bit Presence (0=Not present, 1=Present)
- Bit 11: Invalid Stop bit (0=Normal, 1=Invalid)
- Bit 12: End of Break
For example:
S0IN=0x0074 // Data = 0x74, No Parity bit
S0IN=0x0174 // Data = 0x174, No Parity bit
S0IN=0x0474 // Data = 0x74, Parity bit = 0
S0IN=0x0674 // Data = 0x74, Parity bit = 1
S0IN=0x0874 // Data = 0x74, No Parity bit
// Invalid Stop bit - Frame Error
S0IN=0x0800 // Break Condintion
S0IN=0x1000 // End of Break Condition
In addition to the SxIN VRTEG, the serial window allows you to
input serial characters by simply typing. Serial characters that are
transmitted by the simulated microcontroller appear in the serial
window.
Serial Output for UARTx VTREG
Data Type: unsigned short
The SxOUT VTREG represents the serial output from the simulated
serial port 0, 1, and so on. Whenever the simulated serial port
transmits a character, the value transmitted is automatically
assigned to SxOUT (which is read-only). You may read the value of
SxOUT to determine the character transmitted by your simulated
program. For example,
S0OUT
outputs the value of the last character transmitted by serial port
0.
SxOUT Format (16-bit Register)
- Bits 0-8: Data (5, 6, 7, 8 or 9 bits)
- Bit 9: Parity bit Value
- Bit 10: Parity bit Presence (0=Not present, 1=Present)
- Bit 11: Invalid Stop bit (0=Normal, 1=Invalid)
- Bit 12: End of Break
For example:
S0OUT & 0x01FF // Data
S0OUT & 0x0400 // Parity bit is present
S0OUT & 0x0200 // Parity bit value (0=0, 0x0200=1)
Note that you cannot assign values to the SxOUT VTREGs. You may
use the SxOUT VTREG in a script to process transmitted data. For
example,
signal void s0out_sig (void) {
while (1)
{
wwatch(S0OUT); /* wait for something in S0OUT */
printf ("Transmitted a %2.2X\n", (unsigned) S0OUT);
}
}
Serial Timing Enable for UARTx VTREG
Data Type: unsigned short
The SxTIME VTREG allows you to control the timing of the simulated
serial port 0, 1, and so on.
-
A value of 1 (which is the default) indicates that the serial
port timing is identical to the target hardware. Use this value
when you want to see the effects of baud rate on the serial port
I/O.
-
A value of 0 indicates that all serial input and output occur
instantaneously. Use this value when you don't care about any baud
rate effects or when you want serial output to be fast.
For example:
S0TIME = 0 /* Set Serial Port 0 for FAST timing */
S0TIME = 1 /* Set Serial Port 0 for accurate timing */