.. index:: retro,8051,8051:in-circuit programmer and emulator, burn: the 8051 programmer/emulator
 
.. _retro:
 
.. Created retro.rst: Wed  9 Feb 2022 18:12:07 AEDT 
.. Full Path: /home/tp/mecrisp-unofficial-doc/retro.rst 
.. Author Copyright 2022 by t.j.porter <terry@tjporter.com.au> 
.. Made by /home/tp/projects/scripts/makerst.sh -->/usr/local/bin/makerst 
.. license: MIT, please see COPYING 
 
Retro
=====
A page to show how easy STM32 and Forth makes embedded design in the 2020's.

AT89C2051 MCU
-------------
This is a 8051 with on board 2KB flash, a couple of timer counters, a USART, comparator, what a great mcu in the 90's. It was far, far easier than wiring up a cpu, ram, rom, timers, I/O etc.

.. image:: pics/retro/AT89C2051.jpg

.. seealso:: :ref:`The 8051<8051>`

Features
^^^^^^^^
* Compatible with MCS®-51Products
* 2K Bytes of Reprogrammable Flash Memory, Endurance: 10,000 Write/Erase Cycles
* 2.7V to 6V Operating Range
* Fully Static Operation: 0 Hz to 24 MHz
* Two-level Program Memory Lock
* 128 x 8-bit Internal RAM
* 15 Programmable I/O Lines
* Two 16-bit Timer/Counters
* Six Interrupt Sources
* Programmable Serial UART Channel
* Direct LED Drive Outputs
* On-chip Analog Comparator
* Low-power Idle and Power-down Modes
* Green (Pb/Halide-free) Packaging Option

In Circuit Programmer and Emulator (Burn)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I had to design and make this,back in the 1990's just so I could program the AT89C2051 chip in-circuit using a PC. I used SDCC, a FLOSS C compiler, for the MCU and Gcc for the PC connected programmer below.

As usual I used a Makefile to orchestrate everything, so when I has written C code on SDCC for the AT89C2051, i.e. a stepper motor driver, I would enter 'make' on the pc and the running stepper motor connected to the programmer would stop for about 1/2 a second while the AT89C2051 was reprogrammed and then the motor would start running again.

.. image:: pics/retro/burn-schematic.jpg


It took me months to design the hardware and write the C source for the PC part but you get all this in a instant with Cortex-M MCU and a $2.80 AUD USB-SWD dongle like this

St-link V2 Chinese Clone for Cortex-M Programming and IN-Circuit Debugging with GDB
-----------------------------------------------------------------------------------
Usually has a APM32F103 or CKS32F103 and the latest STM firmware fitted.

.. image:: pics/st-link_dongle.png