Datasheet

F28M36P63C, F28M36P53C, F28M36H53C, F28M36H53B, F28M36H33C, F28M36H33B
SPRS825C –OCTOBER 2012–REVISED FEBRUARY 2014 www.ti.com
7 Peripheral Information and Timings
7.1 Analog and Shared Peripherals
Concerto Shared Peripherals are accessible from both the Master Subsystem and the Control Subsystem.
The Analog Shared Peripherals include two 12-bit ADCs (Analog-to-Digital Converters), and six
Comparator + DAC (10-bit) modules. The ADC Result Registers are accessible by CPUs and DMAs of the
Master and Control Subsystems. All other analog registers, such as the ADC Configuration and
Comparator Registers, are accessible by the C28x CPU only. The Digital Shared Peripherals include the
IPC peripheral and the EPI. IPC is accessible by both CPUs; EPI is accessible by both CPUs and both
DMAs.
IPC is used for sending and receiving synchronization events between Master and Control subsystems to
coordinate execution of software running on both processors, or exchanging of data between the two
processors. EPI is used by this device to communicate with external memory and other devices.
For detailed information on the processor peripherals, see the Concerto F28M36x Technical Reference
Manual (literature number SPRUHE8).
7.1.1 Analog-to-Digital Converter
Figure 7-1 shows the internal structure of each of the two ADC peripherals that are present on Concerto.
Each ADC has 16 channels that can be programmed to select analog inputs, select start-of-conversion
trigger, set the sampling window, and select end-of-conversion interrupt to prompt a CPU or DMA to read
16 result registers. The 16 ADC channels can be used independently or in pairs, based on the
assignments inside the SAMPLEMODE register. Pairing up the channels allows two analog inputs to be
sampled simultaneously—thereby, increasing the overall conversion performance.
7.1.1.1 Sample Mode
Each ADC has 16 programmable channels that can be independently programmed for analog-to-digital
conversion when corresponding bits in the SAMPLEMODE register are set to Sequential Mode. For
example, if bit 2 in the SAMPLEMODE register is set to 0, ADC channels 4 and 5 are set to sequential
mode. Both the SOC4CTL and SOC5CTL registers can then be programmed to configure channels 4 and
5 to independently perform analog-to-digital conversions with results being stored in the RESULT4 and
RESULT5 registers. "Independently" means that channel 4 may use a different SOC trigger, different
analog input, and different sampling window than the trigger, input, and window assigned to channel 5.
The 16 programmable channels for each ADC may also be grouped in 8 channel pairs when
corresponding bits in the SAMPLEMODE register are set to Simultaneous Mode. For example, if bit 2 in
the SAMPLEMODE register is set to 1, ADC channels 4 and 5 are set to Simultaneous Mode. The
SOC4CTL register now contains configuration parameters for both channel 4 and channel 5, and the
SOC5CTL register is ignored. While channel 4 and channel 5 are still using dedicated analog inputs (now
selected as pairs in the CHSEL field of SOC4CTL), they both share the same SOC trigger and Sampling
Window, with the results being stored in the RESULT4 and RESULT5 registers.
The Simultaneous mode is made possible by two sample-and-hold units present in each ADC. Each
sample-and-hold unit has its own mux for selecting analog inputs (see Figure 7-1). By programming the
SAMPLEMODE register, the 16 available channels can be configured as 16 independent channels,
8 channel pairs, or any combination thereof (for example, 10 sequential channels and 3 simultaneous
pairs).
154 Peripheral Information and Timings Copyright © 2012–2014, Texas Instruments Incorporated
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