| ??? 02/15/05 09:53 Modified: 02/15/05 09:55 Read: times |
#87493 - serial loader exit timing Responding to: ???'s previous message |
Some of this is redundant and can be found on this site, yet this is the specific info as found in the DS89C420 Ultra-High Speed Microcontroller User's guide (the 192 page reference);
Pg. 121 External Reset: "When the reset is removed (external reset) the processor will exit the reset state within 4 clock cycles and begin execution at address 0000h". Pg. 76 Internal Flash Memory: "The /EA pin is sampled on each exit from the reset state to determine whether the program fetching should begin internally or externally." Pg. 179 Exiting The Loader: (serial or boot-strap loader) "In order to exit the loader on the DS89C420 device, first float the /PSEN signal, then float or drive the RST pin low. The RST pin has an internal pull-down. The /PSEN signal is an output and will drive itself high. When the loader stimulus is removed, the processor will perform a hardware reset and begin execution at location 0000h. Note that both of these conditions must occur or the loader will not be exited." Anyhow, it works. What was the question? |
| Topic | Author | Date |
| Loader for DS89C420/30/40/50 | 01/01/70 00:00 | |
| Dallas loader | 01/01/70 00:00 | |
| Loader problems | 01/01/70 00:00 | |
| Dallas loader | 01/01/70 00:00 | |
| Dallas loader | 01/01/70 00:00 | |
| Don't discount 98 | 01/01/70 00:00 | |
| Don't discount 98 | 01/01/70 00:00 | |
| Linux version | 01/01/70 00:00 | |
| Linux version | 01/01/70 00:00 | |
| Terminal emulator in Linux? | 01/01/70 00:00 | |
serial loader exit timing | 01/01/70 00:00 | |
| Loader circuitry for ultra high-speed... | 01/01/70 00:00 | |
| Loader circuitry for ultra high-speed... | 01/01/70 00:00 | |
| Confusing figure 1 | 01/01/70 00:00 |