IV ANALOG BLOCK: A/D CONVERTER
Table 2.3 Relationship between CS/CE and Input Channel
CS2/CE2 | CS1/CE1 | CS0/CE0 | Channel selected |
1 | 1 | 1 | AD7 |
1 | 1 | 0 | AD6 |
1 | 0 | 1 | AD5 |
1 | 0 | 0 | AD4 |
0 | 1 | 1 | AD3 |
0 | 1 | 0 | AD2 |
0 | 0 | 1 | AD1 |
0 | 0 | 0 | AD0 |
Example: Operation of one A/D conversion
CS[2:0] = "0", CE[2:0] = "0": Converted only in AD0
CS[2:0] = "0", CE[2:0] = "3": Converted in the following order: AD0→ AD1→ AD2→ AD3
CS[2:0] = "5", CE[2:0] = "1": Converted in the following order: AD5→ AD6→ AD7→ AD0→ AD1
Note: Only
Setting the A/D conversion mode
The A/D converter can operate in one of the following two modes. This operation mode is selected using MS (D5) / A/D trigger register (0x40242).
1. Normal mode (MS = "0")
All inputs in the range of channels set using the CS and CE bits are A/D converted once and then stopped.
2. Continuous mode (MS = "1")
A/D conversions in the range of channels set using the CS and CE bits are executed successively until stopped by the software.
At initial reset, the normal mode is selected.
Selecting a trigger
Use TS[1:0] (D[4:3]) / A/D trigger register (0x40242) to select a trigger to start A/D conversion from among the four types shown in Table 2.4.
|
| Table 2.4 Trigger Selection |
TS1 | TS0 | Trigger |
1 | 1 | External trigger (K52/#ADTRG) |
1 | 0 | |
0 | 1 | |
0 | 0 | Software |
1. External trigger
The signal input to the #ADTRG pin is used as a trigger.
When this trigger is used, the K52 pin must be set for #ADTRG in advance by writing "1" to CFK52 (D2) / K5 function select register (0x402C0).
A/D conversion is started at a falling edge of the #ADTRG signal.
2. Programmable timer
The underflow signal of
For details on how to set a timer, refer to the explanation of each programmable timer in this manual.
3. Software trigger
Writing "1" to ADST (D1) / A/D enable register (0x40244) in the software serves as a trigger to start A/D conversion.
EPSON | S1C33L03 FUNCTION PART |