| ??? 10/01/10 05:51 Read: times |
#178815 - It's going to have to be a delicate introduction to MCU's Responding to: ???'s previous message |
Kai Klaas said:
Richard said:
I just got a call from a former colleague who wants to use a small MCU (just a few pins) to receive and interpret output from a V to F converter (remote) into ten digital output signals and an analog output. Have any of you guys run across a small MCU (low pin count) that can do this? I've found a number of small (20 or 24 pin) MCU's that have ADC, but what DAC? By ten digital outputs you mean that the frequency shall be translated into a 10bit word? Well, there are many ways to accomplish this: 1. You form a 10bit R2R-ladder using 10 port pins of the micro. -> A bit critical if high precision is desired. That was under discussion. 2. You feed a tiny high precision serial DAC. -> Probably offering the best cost-effectiveness. That was also discussed. 3. You feed a 16bit-PWM and low pass filter the resulting pulse train, like Michael already mentioned. SILABS micros contain superb 16bit-PWMs. -> Rather high settling time if high precision and low ripple is needed. I don't know that 16-bit dynamic range is required, nor do I know that the 500Hz update frequency he started out with is necessary. I'd guess that an average of 10 voltages and display at 50 Hz might suit him. That's yet to be determined. 4. You take a MCU already containing a DAC. SILABS have very precise ones. -> Might result in a MCU having many more port pins than you actually need...
Kai Klaas I don't want him to wind up with more than 80 pins, particularly since he can "get by" with 20 if he uses I2C or SPI communication with the external LED driver and DAC. The thing's really quite simple, so far, but I'm spooked because such devices tend to change mid-stream, which makes a mess of a hardware-only approach. RE |
| Topic | Author | Date |
| What would you use? | 01/01/70 00:00 | |
| Try this | 01/01/70 00:00 | |
| Another query | 01/01/70 00:00 | |
| If even you Americans don't understand each other... | 01/01/70 00:00 | |
| My point was ... | 01/01/70 00:00 | |
| PSoC | 01/01/70 00:00 | |
| The display is really simple | 01/01/70 00:00 | |
| there is a '51 PSoC | 01/01/70 00:00 | |
| 8051=PSoC3 | 01/01/70 00:00 | |
| There are several ways... | 01/01/70 00:00 | |
| It's going to have to be a delicate introduction to MCU's | 01/01/70 00:00 | |
| parametric search | 01/01/70 00:00 | |
| Couldn't find that ... this time | 01/01/70 00:00 | |
| built-in DAC | 01/01/70 00:00 | |
| also in some 3xx's | 01/01/70 00:00 | |
| C8051F330-GP | 01/01/70 00:00 | |
| I've decided that's a good choice | 01/01/70 00:00 | |
| Maybe drive LEDs without LED driver? | 01/01/70 00:00 | |
I haven't yet considered that ... | 01/01/70 00:00 | |
| Analog DevicesADUC814 | 01/01/70 00:00 | |
| That's one of the sheets I sent him | 01/01/70 00:00 | |
| 2 chips maybe better | 01/01/70 00:00 | |
| what resolution? | 01/01/70 00:00 | |
| They're under consideration | 01/01/70 00:00 | |
| '51 with d to a | 01/01/70 00:00 |