| p>In an earlier article I have discussed how MSP | | | | each. These inputs are differential inputs and |
| 430 is a good fit for low power and mixed signal | | | | hence good for low signal applications. |
| precision applications. This article is a look at the | | | | Six of these channels can be connected to |
| features of these resources/on-board peripherals. | | | | off-chip signals. The seventh input is connected to |
| A clear picture of the availability of features can | | | | an temperature sensor and the eighth pair is |
| tell you, how a design you have in your mind can | | | | shorted internally as a reference for calibrating the |
| be fitted into the microcontroller system for a | | | | other inputs. With a 16 bit converter you can |
| minimal design. | | | | actually measure 65,536 steps of the input signal. |
| Biggest problem with digital only microcontrollers is | | | | That would mean you would be able to measure |
| that you need additional external components in | | | | 15.26 micro volt for a 0-1 volt input signal. That is |
| the form of analog to digital and digital to analog | | | | a lot of precision! |
| converter chips. By including such devices | | | | You have four different modes of conversion. In |
| on-board this microcontroller directly reduces | | | | a channel all the 8 inputs get the conversion signal |
| system chip count. There are several serial | | | | at the same time. Overall the seven channels can |
| communication resources on board that simplify | | | | be organized to convert in four different modes. |
| communication. Most control systems typically | | | | Single channel, single conversion, single channel |
| acquire signals to measure things and then send | | | | continuous conversion, a group of channels single |
| out commands to control things. With these signal | | | | conversion and a group of channel continuous |
| converters and the serial communications | | | | conversions are the operating modes. Each |
| infrastructure MSP 430 is architected for such | | | | converted data gets stored in designated |
| embedded roles. In the embedded systems you | | | | memory location and raises an interrupt. A low |
| get a lot of service requests that must be met in | | | | power conversion mode can be selected to |
| real-time. A well structured and flexible interrupt | | | | conserve power. |
| system and timers are then other pre-requisites | | | | ADC12 provides 12 bits of precision on each of its |
| for such systems. | | | | input channels. Up to 16 channels can be there |
| We shall discuss these resources in turn starting | | | | that are sampled by the device. Conversion can |
| with the analog units . | | | | be commanded by software or automatically by |
| Analog Resources | | | | the two timers Timer_A and Timer_B. ADC10 |
| ADC12, ADC10 and DAC12 or 12 bit and 10 bit | | | | peripherals are similar but with 10 bits of resolution |
| analog to digital converters and 12 bit Digital to | | | | precision. This can be driven by software or the |
| analog converters and SD16/16A or a 16 bit | | | | Timer_A. |
| Sigma Delta multi-channel analog to digital | | | | DAC12 are peripherals that convert digital signals |
| converter are the typical signal converter | | | | back to analog. These are 12 bit devices voltage |
| resources on the controllers across the families. | | | | output devices, so up to 4096 levels can be used |
| The SD-16 is really speaking a data acquisition | | | | to define the output signal. A device in the family |
| system in itself. These can have up to seven | | | | may have more than one DAC12 in it. These |
| channels, each of which can handle 8 analog inputs | | | | devices can be used in 8 bit or 12 bit mode. |