Analog programmable blocks

Analog programmable blocks are grouped in columns of three programmable blocks. Depending on family of microcontroller, there could be 1, 2 or 4 analog columns. Each column has input multiplexer, one frequency line, output analog and a comparator line. 

Analog multiplexers of port P0

Signals from port 0 are connected to analog ACB blocks over appropriate input multiplexers. Multiplexers can select even (Port0_even) or odd (Port0_Odd) pins, while two middle columns have the ability to choose

either pins of port P0.

Analog inputs of port P2

Beside port P0, as analog inputs could be used four lower pins of port P2. This pins can be connected directly to analog programmable blocks.

Analog columns

One column of analog blocks is made of three types of blocks: ACB, ASC i ASD. Outputs of these blocks can be routed to some of adjacent blocks, output analog line or comparator line.

ACB blocks are used to store amplifiers with rail-to-rail inputs and outputs, digital controlled resistors and internal multiplexers. Depending on interconnections made inside of ACB blocks, it is possible to implement

inverting, noninverting, instrument amplifier or comparator. As input to ACB blocks can be used analog multiplexer or output signal of some of adjacent blocks.

ASC and ASD blocks are of switched capacitor (SC) type. They contains amplifiers with rail-to-rail input and outputs, condensators and internal multiplexers. AD, DA and analog filters could be implemented depending

on configuration inside of these blocks. As inputs to SC blocks, input from some adjacent block could be used. It should be noted, that signals from analog multiplexers couldn’t be brought directly to SC blocks, but

over ACB blocks.

Analog outputs

For every analog column is common to have an AnalogOutBus line. Analog output lines can be are connected, through a buffer, to four middle pins of port A.

Comparator outputs

Every analog column has one comparator line, to which could be connected digital output from one of analog blocks. Comparator output could be connected to digital blocks (most common way of doing it is as counter signal, or timer). Before connecting, there is a possibility to modify or combine comparator output of some column (A) with next comparator line (B), using some logic operation.