We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.
I have been studying the tutorial for the 8051 at http://www.8052.com. For starters, I am writing a simple assembler code for an AT89S8253 microcontroller which will read inputs on Port1 and output it to Port3. I am using the demo C51 software from KEIL and am also using the AT89ISP cable to download the hex file onto my device. I am running the XTAL1 input at 4 MHz and have the device setup on a Teradyne J750 tester. I wrote a simple program, but I am getting timer or clock-like outputs from Port2. I am not sure how to proceed (whether I need an include file, the correct syntax, etc.). Also, can you recommend good references (books, websites)? I am new at this, so I would really appreciate the help.
Thank you all for your immediate responses. I am utilizing MicroVision3 V3.50. The program compiles without any errors. I can select the AT89S8253 from the "select device for target menu." When I run the part on the emulator, I can change the pin values on Port1 and observe the corresponding changes on Port3. If the pins are toggling this way on the emulator, shouldn't I be able to observe these physical changes on the outputs for Port3?
Some of things that I noticed on peripherals were:
1. When I set bit 5 to low on Port1, the Timer/Counter1 peripheral T1 Pin box becomes unchecked.
2. Setting bit 4 to low on Port1, also unchecks the T0 Pin box on the Timer/Counter0 peripheral and also unchecks the SS# Pin on the SPI peripheral
3. Setting bit 3 to low on Port1, unchecks the INT1# box on the Timer/Counter1 peripheral
4. Setting bit 2 to low on Port1, unchecks the INT0# box on the Timer/Counter0 peripheral, checks the IE0 box on the Interrupt System menu, and changes the Req from 0 to 1 for the P3.2/Int0 Int Source on the Interrupt System menu also.
default clock settings are: XTAL Frequency = 24,000,000 CPU Clock = 2,000,000
When I start the debug session I get the following message:
"EVALUATION VERSION Running with Code size Limit: 2K"
The Teradyne J750 digital tester that I am utilizing, allows me to stimulate and debug the device. I can input certain settings such as:
VCC input voltages load currents timing equations
Here is the code that I obtained from an example:
sfr P1 = 0x90; /* SFR definition for Port 1 */ sfr P3 = 0xB0; /* SFR definition for Port 3 */ /*------------------------------------------------ MAIN C Function ------------------------------------------------*/ void main (void) { unsigned char pval; /* temp variable for port values */ P1 = 0xFF; /* Setup P1 for Input */ /*-------------------------------------- Use the Toolbox buttons in the debugger to change the value of P1. Open the Port 1 and Port 3 dialogs from the Peripherals Menu to view their status. --------------------------------------*/ while (1) { pval = P1; /* Read P1 into pval */ P3 = pval; /* Write pval to P3 */ } }
The code is obviously in C and not assembler, my apologies. I have been looking over examples that utilize both types.