| ??? 06/09/13 19:58 Read: times |
#189891 - Low-power MCU needed |
For a current project, I chose the Atmel AT89LP214 based on datasheet data. Low power consumption was one of the requirements.
The MCU spends most of the time in idle mode with a timer running. Then when the timer overflows, a port pin is flipped, the timer registers are reloaded, and idle mode is entered again. Based on the datasheet, I chose a 2MHz ceramic resonator. The current should be about 2.7mA in active mode and about 0.6mA in idle mode. The actual current is 2.7mA all the time - not what I expected. Using the internal 8MHz oscillator, the current should be 6/2mA, and it's actually the same 2.7mA, with the software running at 4x speed. If I change the software to work correctly at 8MHz, the consumption drops to 2.55mA. Better, but not great. Are there better alternatives? The requirements are quite simple: - 5V operation - 4 available push/pull output pins - 1kB flash - small(ish) size I chose the LP214 because of the DIL-14 house also. A DIL-device is easy to program in a ZIF socket, and there isn't space for a DIL-14 and a programming header on the board. The IC shouldn't be too small either, as the boards have to be hand-assembled. A narrow SOIC-14 -20 would be ideal. The IC + programming header would be the same size as the DIL-14. A device with an internal precision clock would be nice - provided it can be divided to be slow enough. A 12-clock device running at 4MHz is fast enough, so much "power" isn't needed... Mikkel |
| Topic | Author | Date |
| Low-power MCU needed | 01/01/70 00:00 | |
| OK, but wrong | 01/01/70 00:00 | |
| Wrong how? | 01/01/70 00:00 | |
| Silabs options | 01/01/70 00:00 | |
| C8051F99x | 01/01/70 00:00 | |
| Silabs | 01/01/70 00:00 | |
| look it up | 01/01/70 00:00 | |
| Looked up | 01/01/70 00:00 | |
| f53, no | 01/01/70 00:00 | |
| C8051F537A is OK | 01/01/70 00:00 | |
| the current in active mode is not the issue | 01/01/70 00:00 | |
| Inactive current | 01/01/70 00:00 | |
| re: wrong | 01/01/70 00:00 | |
| Consumers | 01/01/70 00:00 | |
| Zilog Z51F0410 | 01/01/70 00:00 | |
| Zilog | 01/01/70 00:00 | |
| Check you are entering idle ? | 01/01/70 00:00 | |
| idle current | 01/01/70 00:00 | |
| Idle test | 01/01/70 00:00 | |
| re: | 01/01/70 00:00 | |
| It floats! It floats! | 01/01/70 00:00 | |
| re:floats | 01/01/70 00:00 | |
| re:floats | 01/01/70 00:00 | |
| Timers | 01/01/70 00:00 | |
| More idle tests | 01/01/70 00:00 | |
| Better regulator? | 01/01/70 00:00 | |
| LR8K4 450V regulator | 01/01/70 00:00 | |
| also try CLKREG | 01/01/70 00:00 | |
| Clk Dividers are a good idea | 01/01/70 00:00 | |
| No dividers | 01/01/70 00:00 | |
| LP52 is cheaper too... | 01/01/70 00:00 | |
| LP52 | 01/01/70 00:00 | |
| No GND pin? | 01/01/70 00:00 | |
| re:idle | 01/01/70 00:00 | |
| Totally idle | 01/01/70 00:00 | |
| Checks | 01/01/70 00:00 | |
| More checks | 01/01/70 00:00 | |
| Power Down ? | 01/01/70 00:00 | |
| test setup | 01/01/70 00:00 | |
| STC | 01/01/70 00:00 | |
| C8051F86x/85x ? | 01/01/70 00:00 | |
| Maybe not such a good choice, after all? | 01/01/70 00:00 | |
| Support? | 01/01/70 00:00 | |
'51 support | 01/01/70 00:00 |