C8051F360 datasheet(63/288 Pages) SILABS

63 / 288 page

Rev. 1.0

C8051F360/1/2/3/4/5/6/7/8/9

6. 10-Bit Current Mode DAC (IDA0, C8051F360/1/2/6/7/8/9)

The C8051F360/1/2/6/7/8/9 devices include a 10-bit current-mode Digital-to-Analog Converter (IDAC).

The maximum current output of the IDAC can be adjusted for three different current settings; 0.5 mA,

1 mA, and 2 mA. The IDAC is enabled or disabled with the IDA0EN bit in the IDA0 Control Register (see

SFR Definition 6.1). When IDA0EN is set to ‘0’, the IDAC port pin (P0.4 for C8051F360, P0.1 for

C8051F361/2/6/7/8/9) behaves as a normal GPIO pin. When IDA0EN is set to ‘1’, the digital output drivers

and weak pullup for the IDAC pin are automatically disabled, and the pin is connected to the IDAC output.

An internal bandgap bias generator is used to generate a reference current for the IDAC whenever it is

enabled. When using the IDAC, the appropriate bit in the P0SKIP register should be set to ‘1’ to force the

Crossbar to skip the IDAC pin.

6.1.

IDA0 Output Scheduling

IDA0 features a flexible output update mechanism which allows for seamless full-scale changes and sup-

ports jitter-free updates for waveform generation. Three update modes are provided, allowing IDAC output

updates on a write to IDA0H, on a Timer overflow, or on an external pin edge.

6.1.1. Update Output On-Demand

In its default mode (IDA0CN.[6:4] = ‘111’) the IDA0 output is updated “on-demand” on a write to the high-

byte of the IDA0 data register (IDA0H). It is important to note that writes to IDA0L are held in this mode,

and have no effect on the IDA0 output until a write to IDA0H takes place. If writing a full 10-bit word to the

IDAC data registers, the 10-bit data word is written to the low byte (IDA0L) and high byte (IDA0H) data reg-

isters. Data is latched into IDA0 after a write to the IDA0H register, so the write sequence should be

IDA0L followed by IDA0H if the full 10-bit resolution is required. The IDAC can be used in 8-bit mode by

initializing IDA0L to the desired value (typically 0x00), and writing data to only IDA0H (see Section 6.2 for

information on the format of the 10-bit IDAC data word within the 16-bit SFR space).

IDA0

IDA0EN

IDA0CM2

IDA0CM1

IDA0CM0

IDA0OMD1

IDA0OMD0

Figure 6.1. IDA0 Functional Block Diagram

C8051F360 Datasheet(PDF) 63 Page - Silicon Laboratories