The ADC module described here is a successive approximation (SAR) style ADC with resolution of 12 bits. This section refers to the analog circuits of the converter as the “core,” and includes the channel-select MUX, the sample-and-hold (S/H) circuit, the successive approximation circuits, voltage reference circuits, and other analog support circuits. The digital circuits of the converter are referred to as the “wrapper” and include logic for programmable conversions, result registers, interfaces to analog circuits, interfaces to the peripheral buses, post-processing circuits, and interfaces to other on-chip modules.
Each ADC module consists of a single sample-and-hold (S/H) circuit. The ADC module is designed to be duplicated multiple times on the same chip, allowing simultaneous sampling or independent operation of multiple ADCs. The ADC wrapper is start-of-conversion (SOC)-based (see the SOC Principle of Operation section of the Analog-to-Digital Converter (ADC) chapter in the TMS320F28004x Microcontrollers Technical Reference Manual).
Each ADC has the following features:
Not every channel may be pinned out from all ADCs. See Section 4 to determine which channels are available.
The block diagram for the ADC core and ADC wrapper are shown in Figure 5-32.