Re: static config reg can not be changed | M68HC11

> The short answer to your question is: Yes, it can be done. > > I have been working on a project recently that uses a 'F1 in > expanded mode, with FLASH mapped to $8000-$FFFF. I, too, have had > the need to be able to write to the FLASH underlying the EEPROM that > is default-mapped to $FE00-$FFFF when the 'F1 is started in > bootstrap mode. > > One thing that many users of the HC11 are unaware of with regard to > the CONFIG register is that it is implemented as both a static latch > and a EEPROM cell. The CONFIG static latch *can* be written to (in > special test or bootstrap mode) independent of the EEPROM cell. > Writing to the CONFIG register using a normal store operation (as > opposed to the EEPROM programming procedure) will update the static > latch, applying the CONFIG change for the current session, until > written again or MCU reset. > > If you use the JBug 'R' command to update CONFIG (e.g. R > CONFIG=$7F), JBug will attempt to update CONFIG using the EEPROM- > write method, which does NOT update the static latch. However, if > you use JBug's MM or F(ill) commands to update it, it will be > written using a normal memory write operation. > > The bottom line: To perform a 'temporary' CONFIG register change, > use this JBug command: > > F 1030 +0 7F > > Issuing the above command will change the CONFIG register to $7F. > > One handy feature of JBug that I have found particularily useful for > development with my 'F1 expanded mode project is the AUTOSTART macro > feature. I use an AUTOSTART macro to automatically initialize > the 'F1 CONFIG and chip-select-control registers. Since AUTOSTART > is executed every time the target is reset, my target is always > configured to operate in expanded mode with the mappings that my > hardware requires. > > The macro I use actually loads a small program into internal RAM > which performs the initialization tasks I need (I do this because > there are several hardware subsystems I need to initialize that > cannot be set up using simple memory writes) but for basic CONFIG > and chip select register programming, the following macro would > likely suffice: > > DEFM AUTOSTART > BEGIN > S ;Make sure CPU is stopped > F 103F +0 7F ;Map EEPROM to 7E00-7FFF > F 105C +0 30B50001 ;Configure chip selects > END > > Create the above macro definition using a text editor (such as the > macro editor built into JBug) and save it (I put it in my project > directory under the name 'F1Start.MCR'). Go into JBug's Settings > dialog, General tab, and check the 'Load macro on boot' checkbox, > and enter the path to your macro definition file in the space > provided. Save these settings under an appropriate name. Now, when > you do a target reset (assuming JBug is 'listening' properly) the > CONFIG and chip select registers will be automatically set for you. > > You will likely have to modify the values for the chip select > register settings (the 2nd 'F' instruction in the macro) to > something other than the ones I show above. The values shown are > suitable for a 32K RAM on -CSGEN at $0000-$7FFF, 32K ROM on -CSPROG > at $8000-$FFFF, memory-mapped peripheral(s) on -CSIO1 at $x000 with > 0 wait states, and a character LCD module on +CSIO2 at $x800 with 3 > wait states. Thank you for the information. I have tried the sane thing, but unfortunately it is giving some error. 1. First I have tried to change the CONFIG register using the command ��F 1030 +0 7F�� But it gave a error message in the popup window ��Echo error writing RAM�� 2. Second I have experimented with AUTOSTART macro. But that also give an error message ��F 103F +0 7F �� cannot be used to write config F 1030 +0 7F Writing control regs 1030..1030 Diagnostics for : Echo error writing RAM What would be the problem here. In our hardware we have mapped only External SRAM from the location 0x8000-FFFF. No other memory mapping is changed. Could you please find out what went wrong here. Thanking you JACKSON

(You need to be a member of hc11 -- send a blank email to hc11-subscribe@yahoogroups.com )

Sign in

Search hc11

Subscribe to hc11

Ads

Discussion Groups

Discussion Groups | M68HC11 | Re: static config reg can not be changed

Re: static config reg can not be changed - jackson_cp - Sep 21 5:48:00 2004