| ??? 03/18/06 01:58 Read: times |
#112443 - Why MX? Responding to: ???'s previous message |
I think they were right at Philips, recommending you an another type of mcu.
The FA (Fx) was an early extension of 8052 by intel, adding nothing more than the PCA. Direct descendants of Fx are the Rx2's of various manufacturers (Atmel/Temic, Philips, SST, Winbond). PCA is also contained in other derivatives, but not directly pin compatible. The MX is a particular architecture with expanded memories of all kind. I think there is no reason to go into it if you need a direct replacement for the FA. However, your problem might be even worse. Your external code RAM is mapped as external data RAM during boot time; but all the modern descendants of Fx (including the Mx) have "internal external" data memory (dubbed XRAM (originally ERAM by intel, but ERAM has a different meaning with MX). So writing into the bottommost bytes of external ram does not start a write cycle (/WR won't go low), it will write into the internal XRAM. So you have either to map the code RAM into some high address while mapped as external data RAM (unless already so), or disable the internal XRAM (see EXTRAM bit in AUXR). Both will require modified bootloader, of course. Jan Waclawek |
| Topic | Author | Date |
| Problem using 87C51Mx as drop-in replace | 01/01/70 00:00 | |
| still Intel? | 01/01/70 00:00 | |
| just a thought | 01/01/70 00:00 | |
| This is going to be tough | 01/01/70 00:00 | |
| Why MX? | 01/01/70 00:00 | |
| Problem using 87C51Mx as drop-in repla | 01/01/70 00:00 | |
| I tend to recall that the MX has some ER | 01/01/70 00:00 | |
| I tend to recall that the MX has some E | 01/01/70 00:00 | |
| if time permits. | 01/01/70 00:00 | |
| Engineers ? | 01/01/70 00:00 | |
| Very true! | 01/01/70 00:00 | |
Thanks Erik but don't bother... | 01/01/70 00:00 |