Root/ubbctl/README

Source at commit 77a7a38f5fba04849d051f75d9b068c40525809a created 10 years 22 days ago.
By Werner Almesberger, ubbctl/README: fix typo in example
1ubbctl - Control UBB signals
2============================
3
4ubbctl queries the state of UBB signals and allows the user to change
5them. It can run in parallel with any other UBB users.
6
7
8Querying
9--------
10
11To query the UBB signals, run
12
13# ubbctl
14
15This will display something like this:
16
17nPWR=1 DAT2=F1 DAT3=F1 CMD=F1 CLK=Z1 DAT0=1 DAT1=0
18
19"0" means that the pin is driven low. "1" means that is it driven
20high. If the pin reads back as something different than what it is
21set to, this is indicated as "0!1" (pin is shorted to VDD) or "1!0"
22(pin is shorted to ground).
23
24"Z0" and "Z1" means that the pin is an input without internal
25pull-up (note however that all pins but nPWR and CLK) have external
2610 kOhm pull-ups) and that it reads back a low or high,
27respectively.
28
29"R0" and "R1" are like "Z0" and "Z1", except that the internal
30pull-up is enabled.
31
32"F0" and "F1" indicate that the pin configured as a function (i.e.,
33for the MMC controller) and does not operate as GPIO.
34
35ubbctl can run in continuous mode, in which it updates the status
36regularly (currently every 200 ms):
37
38# ubbctl -c
39
40To exit continuous mode kill the process, e.g., which Ctrl-C.
41
42
43Setting
44-------
45
46ubbctl can change the configuration of the UBB pins. The syntax is
47the same as the one used for the status display except that there
48are no readback values. E.g., nPWR=1 would disable power, CLK=R
49would configure CLK as input with pull-up, etc.
50
51A pin can be changed several times. For example, if the idle state
52of DAT0 is 0
53
54# ubbctl dat0=0
55
56then
57
58# ubbctl dat0=1 dat0=0
59
60would send a short positive pulse.
61
62ubbctl also recognizes the keywords ON and OFF to control power to
63the 8:10 interface. They're synonymous to nPWR=0 and nPWR=1,
64respectively.
65

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