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Source at commit 77a7a38f5fba04849d051f75d9b068c40525809a created 10 years 22 days ago. By Werner Almesberger, ubbctl/README: fix typo in example | |
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1 | ubbctl - Control UBB signals |
2 | ============================ |
3 | |
4 | ubbctl queries the state of UBB signals and allows the user to change |
5 | them. It can run in parallel with any other UBB users. |
6 | |
7 | |
8 | Querying |
9 | -------- |
10 | |
11 | To query the UBB signals, run |
12 | |
13 | # ubbctl |
14 | |
15 | This will display something like this: |
16 | |
17 | nPWR=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 |
20 | high. If the pin reads back as something different than what it is |
21 | set 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 |
25 | pull-up (note however that all pins but nPWR and CLK) have external |
26 | 10 kOhm pull-ups) and that it reads back a low or high, |
27 | respectively. |
28 | |
29 | "R0" and "R1" are like "Z0" and "Z1", except that the internal |
30 | pull-up is enabled. |
31 | |
32 | "F0" and "F1" indicate that the pin configured as a function (i.e., |
33 | for the MMC controller) and does not operate as GPIO. |
34 | |
35 | ubbctl can run in continuous mode, in which it updates the status |
36 | regularly (currently every 200 ms): |
37 | |
38 | # ubbctl -c |
39 | |
40 | To exit continuous mode kill the process, e.g., which Ctrl-C. |
41 | |
42 | |
43 | Setting |
44 | ------- |
45 | |
46 | ubbctl can change the configuration of the UBB pins. The syntax is |
47 | the same as the one used for the status display except that there |
48 | are no readback values. E.g., nPWR=1 would disable power, CLK=R |
49 | would configure CLK as input with pull-up, etc. |
50 | |
51 | A pin can be changed several times. For example, if the idle state |
52 | of DAT0 is 0 |
53 | |
54 | # ubbctl dat0=0 |
55 | |
56 | then |
57 | |
58 | # ubbctl dat0=1 dat0=0 |
59 | |
60 | would send a short positive pulse. |
61 | |
62 | ubbctl also recognizes the keywords ON and OFF to control power to |
63 | the 8:10 interface. They're synonymous to nPWR=0 and nPWR=1, |
64 | respectively. |
65 |
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