NAME
mcp3kadc —
Microchip 3x0x SAR analog to
digital converter
SYNOPSIS
mcp3kadc* at spi? slave ? flags N
DESCRIPTION
The
mcp3kadc driver reports the current voltage on the chip's
ADC channels through the
envsys(4) API. The driver
calculates these values according to the currently selected reference voltage
(
Vref). It can be changed through the
sysctl(8) node
hw.mcp3kadc0.vref.
The following table shows the supported chips. The type of the chip can be
selected with the
flags argument in the config file.
| Designation |
Resolution |
Input Channels |
flags |
MCP3001 |
10 bits |
1 |
0 |
MCP3002 |
10 bits |
2 |
1 |
MCP3004 |
10 bits |
4 |
2 |
MCP3008 |
10 bits |
8 |
3 |
MCP3201 |
12 bits |
1 |
4 |
MCP3202 |
12 bits |
2 |
5 |
MCP3204 |
12 bits |
4 |
6 |
MCP3208 |
12 bits |
8 |
7 |
MCP3301 |
13 bits |
1 |
8 |
MCP3302 |
13 bits |
4 |
9 |
MCP3304 |
13 bits |
8 |
10 |
SYSCTL VARIABLES
The following
sysctl(3) variables
are provided:
-
-
- hw.mcp3kadc0.vref
- Defines the reference voltage on the chip's
Vref pin in millivolts (mV). It defaults to the
ADC's maximum output value + 1 in millivolts (e.g., 4096 for a 12-bit
ADC).
SEE ALSO
envsys(4),
spi(4),
sysctl(8)
HISTORY
The
mcp3kadc driver first appeared in
NetBSD
8.0.
AUTHORS
The
mcp3kadc driver was written by
Frank
Wille.