Date: Sun, 4 Aug 200221:14:29 +0700
From: "Taufik IR" <taufikir@telkom.net>
To: <kswichit@kmitl.ac.th>
Dear Wichit,
This is my modification for your easy downloader v2 for in system programmer(not only for programming, but can running program in target microcontroller)!
Just switching sw1 in mode program or in mode running, sw2 for resettingtarget microcontroller and sw3 for testing external ram. j1 for power supplydc/ac 15v, j2 and j3 for connecting external i/o to target microcontroller,j4 pin 1 and 2 is for external power supply (dc 15v) activated only inmode running, j4 pin 3 is for pin oe/cs (output enable/chip select, somethinglike 74245 or 74573) if you still connect i/o while programming so it won'thappen verify error, and j4 pin 4 is for pin le (latch enable in 74573/373)if you connect an extenal ram (please change sw3 too).
I use rs232 ttl level using 2 fet bs250 and bs170 and a few resistor,but you can change with any rs232 ttl level such as max232, or ds275.
I hope this can help someone who wants to build his own programmer fordeveloping something.
