Need an MSP430 with the following features

You can have a look at: http://focus.ti.com/en/multimedia/flash/selection_tools/mcu/mcu.html

-Leo

Hi,

I'm glad to hear of your support of TI products! :-)

You will not need to use the SPI interface to output the clock - there are pins on the devices that you can select to output your system clock. Either way, you would need an MSP430 part that can run the system clock at 20MHz to output 20MHz (you can't run your spi faster than your system clock anyway). This is going to put you into the range of an F5xx or FR5xx family part. There are options within these device families that include all of the features you list above (ADC, interrupt-capable GPIOs, UART).

Alternately, since I saw in your other thread that this clock frequency is for an external ADC - you could use one of the parts that has a built-in ADC if it fits the precision/speed requirements you are looking for, saving you in overall system cost. Or if you can handle using 16MHz instead of 20, you could take a look at one of our G2xx value line parts. As for pricing, the best thing to do would be to talk to your local TI sales or TI authorized distributor, as they will be able to tell you a price based on the volume of parts you require. But it looks like you have a few different options here so hopefully you can find a good fit!

Regards,

Katie

1) yes and no. All MSPs with a maximum frequency of 25MHz have a digitally controlled oscillator whcih can output frequencies from a few hundred Hz to up to 100MHz. However, only a limited number of discrete frequencies is available. All others are done by switchign between two frequencies on a 32 bit pattern and/or adjusting the DCO based on a reference clock using an FLL mechanism (4x and 5x family have these implemented). Also, the DCO is fairly unprecise, so the best you can get is an average frequency over an interval of several microseconds. Most MSPs accept an external HF crystal or an external TTL clock signal too.
Once you have a stable frequency (by an FLL stabilized DCO or an external crystal), the timers allow outputting frequencies as an integer division of the system clock from f_system to f_system/65536 with additional dividers up to 64 in powers of 2.
Whether this is usable for you depends on the aplication.

2) ALL 5x family and most other MSPs have at least one hardware UART. Some (e.g. the 5438) have up to four.

3) Except a few, all pins of an MSP can be used as GPIO or used for different purposes. So any MSP with >32 pins will have 25 GPIO. However, UART and clock output are shared with GPIO funcitonality. The 5438 has 81 GPIO.

4) on all MSPs, the first two GPIO ports have interrupt capability, giving you 16 interrupts (if all 16 port pins are externally available - on smaller cases, some are not). Also, on other port pins, the shared module functionality may offer additional interrupts (such as teh capture itnerrupts for pins that are assigned from GPIO to timer usage.

The limiting factor is the price. For below $1, you are limited to the G series. And here you won't find one with 25GPIO plus 4 interrupts plus uart, simply because the G devices are in DIL packages with a maximum pin count of 32 pins.

Teh STC would be a surprising device if it has all this for this price.
I just read the datasheet (with google translation I was able to locate an English datasheet). The STC11F02 comes 16 to 20 Pin Package wiht 12 to 16 I/O ports (sharing the IRQ and UART pins), has 2k Flash, 256 bytes RAM.

The first STCs with >25I/O are the STC11F16XE and the STC10F04 (40 pin PDIP/44pin PLCC package). And I doubt they are available for $.6, not even in 10k quantities and from a Chinese foundry.

Hi Katie,

Thanks for providing  valuable inputs. I read the data sheet of MSP430F5131. The features are as per my requirement. Reg the cost i've to talk to my vendor. Actauly iam feeding the clock output to ADS1178. TI's ADC

Thanks and Regards

shasthri

Hi Jen,

Thanks for providing a detailed analysis on the clock out put  sourced by the DCO. Esp the point 1.

Regards

Shasthri