Tips and tricks/de

Revision as of 21:06, 15 February 2013

== (**COPIED FROM ENGLISH PAGE**) ==This section describes tips and tricks received from users.

Kyle Kronyak : Using all the RAM from an external RAM chip.

I have found a way to use the 607 bytes of external SRAM that are normally not available when using hardware SRAM support with BASCOM-AVR. It's actually quite simple. Basically the user just has to disconnect A15 from /CE on the SRAM module, and tie /CE to ground. This makes the chip enabled all the time. Addresses 1-32768 will then be available! The reason is because normally when going above 32768, the A15 pin would go high, disabling the chip. When A15 is not connected to /CE, the chip is always enabled, and allows the address number to "roll over". Therefore address 32162 is actually 0, 32163 is actually 1, 32164 is actually 2, etc. I have only tested this on a 32k SRAM chip. It definitely won't work on a 64k chip, and I believe it already works on any chip below 32k without modification of the circuit.

Programming problems

- When you have unreliable results, use a shielded LPT cable

- The AVR chips have a bug, if the erase is not complete. It tend's to hang at some point. Sometimes although the system reports erased but blank check report "not empty". As per Atmel Data Errata You must drop the vcc by 0.5V ( a diode 1N4148 in Series ) if the erase is not happening. ( Such Chip's are unreliable and hence can be used only if you are sure ). This can happen after you have programmed the chip many times.