Date:2010-09-05 04:14:57 (8 years 11 months ago)
Author:Werner Almesberger
Commit:86e556ce92af39a3353e0c6494ba20de59d47d4c
Message:First part of the board bringup: power and clock.

- atusd/ERRATA: variations of the circuit being debugged from the design
- tools/Makefile, tools/try.c, tools/lib/atusd.c: user-space tool to enable
the board and (in the future) establish communication
- atusd/sim/clk.sch: simulation of CLK attenuation circuit with capacitative
load from scope probe
Files: atusd/ERRATA (1 diff)
atusd/sim/clk.sch (1 diff)
atusd/tools/Makefile (1 diff)
atusd/tools/lib/atusd.c (1 diff)
atusd/tools/try.c (1 diff)

Change Details

atusd/ERRATA
1- changed C7 to 1 nF to debug a signal attenuation problem. Turned out to be
2  a bad trace. According to simulations, 22 pF should be more than enough.
3
4- added wire connecting uSD-side ground plane to ground plane at outer edge,
5  to improve CLK signal return. (Probably unnecessary, too.)
atusd/sim/clk.sch
1<Qucs Schematic 0.0.15>
2<Properties>
3  <View=0,0,1010,882,1,0,0>
4  <Grid=10,10,1>
5  <DataSet=clk.dat>
6  <DataDisplay=clk.dpl>
7  <OpenDisplay=1>
8  <showFrame=0>
9  <FrameText0=Title>
10  <FrameText1=Drawn By:>
11  <FrameText2=Date:>
12  <FrameText3=Revision:>
13</Properties>
14<Symbol>
15</Symbol>
16<Components>
17  <GND * 1 560 480 0 0 0 0>
18  <.DC DC1 1 90 40 0 36 0 0 "26.85" 0 "0.001" 0 "1 pA" 0 "1 uV" 0 "no" 0 "150" 0 "no" 0 "none" 0 "CroutLU" 0>
19  <Vrect V2 1 560 390 18 -26 0 1 "3.3 V" 1 "33 ns" 1 "33 ns" 1 "1 ns" 0 "1 ns" 0 "0 ns" 0>
20  <.TR TR1 1 100 120 0 57 0 0 "lin" 1 "0" 1 "0.1 us" 1 "9991" 0 "Trapezoidal" 0 "2" 0 "1 ns" 0 "1e-16" 0 "150" 0 "0.001" 0 "1 pA" 0 "1 uV" 0 "26.85" 0 "1e-3" 0 "1e-6" 0 "1" 0 "CroutLU" 0 "no" 0 "yes" 0 "0" 0>
21  <R R3 1 490 260 -26 15 0 0 "100 Ohm" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
22  <GND * 1 420 480 0 0 0 0>
23  <C C2 1 420 370 17 -26 0 1 "50 pF" 1 "" 0 "neutral" 0>
24  <GND * 1 280 480 0 0 0 0>
25  <R R1 1 280 330 15 -26 0 1 "56 kOhm" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
26  <R R2 1 280 430 15 -26 0 1 "10 kOhm" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
27  <C C1 1 350 260 -26 17 0 0 "22 pF" 1 "" 0 "neutral" 0>
28</Components>
29<Wires>
30  <520 260 560 260 "" 0 0 0 "">
31  <560 260 560 360 "" 0 0 0 "">
32  <560 420 560 480 "" 0 0 0 "">
33  <420 400 420 480 "" 0 0 0 "">
34  <420 260 460 260 "" 0 0 0 "">
35  <420 260 420 340 "" 0 0 0 "">
36  <380 260 420 260 "Vmeas" 350 140 39 "">
37  <280 360 280 400 "Vout" 170 330 17 "">
38  <280 260 280 300 "" 0 0 0 "">
39  <280 260 320 260 "" 0 0 0 "">
40  <280 460 280 480 "" 0 0 0 "">
41  <560 260 560 260 "Vin" 590 200 0 "">
42</Wires>
43<Diagrams>
44  <Rect 120 752 719 212 3 #c0c0c0 1 00 1 0 0.2 1 1 -0.1 0.5 1.1 1 -0.1 0.5 1.1 315 0 225 "" "" "">
45    <"Vin.Vt" #0000ff 0 3 0 0 0>
46    <"Vmeas.Vt" #ff0000 0 3 0 0 0>
47    <"Vout.Vt" #ff00ff 0 3 0 0 0>
48  </Rect>
49  <Rect 670 480 278 250 3 #c0c0c0 1 00 1 0 0.2 1 1 -0.1 0.5 1.1 1 -0.1 0.5 1.1 315 0 225 "" "" "">
50    <"Vout.Vt" #0000ff 0 3 0 0 0>
51  </Rect>
52</Diagrams>
53<Paintings>
54</Paintings>
atusd/tools/Makefile
1CC=mipsel-openwrt-linux-gcc
2CFLAGS=-Wall
3
4MAIN = try
5OBJS = $(MAIN).c lib/atusd.o
6
7$(MAIN): $(OBJS)
atusd/tools/lib/atusd.c
1#include <stdint.h>
2#include <stdlib.h>
3#include <stdio.h>
4#include <fcntl.h>
5#include <sys/mman.h>
6
7
8enum {
9    VDD_OFF = 1 << 6, /* VDD disable, PD06 */
10    MxSx = 1 << 8, /* CMD, PD08 */
11    CLK = 1 << 9, /* CLK, PD09 */
12    SCLK = 1 << 10, /* DAT0, PD10 */
13    SLP_TR = 1 << 11, /* DAT1, PD11 */
14    IRQ = 1 << 12, /* DAT2, PD12 */
15    nSEL = 1 << 13, /* DAT3/CD, PD13 */
16};
17
18
19#define SOC_BASE 0x10000000
20
21#define REG(n) (*(volatile uint32_t *) (dsc->mem+(n)))
22
23#define CGU(n) REG(0x00000+(n))
24#define GPIO(n) REG(0x10000+(n))
25#define MSC(n) REG(0x21000+(n))
26
27#define PDDATS GPIO(0x314) /* port D data set */
28#define PDDATC GPIO(0x318) /* port D data clear */
29#define PDFUNS GPIO(0x344) /* port D function set */
30#define PDFUNC GPIO(0x348) /* port D function clear */
31#define PDDIRS GPIO(0x364) /* port D direction set */
32#define PDDIRC GPIO(0x368) /* port D direction clear */
33
34#define MSC_STRPCL MSC(0x00) /* Start/stop MMC/SD clock */
35#define MSC_CLKRT MSC(0x08) /* MSC Clock Rate */
36
37#define CLKGR CGU(0x0020) /* Clock Gate */
38#define MSCCDR CGU(0x0068) /* MSC device clock divider */
39
40
41#define PAGE_SIZE 4096
42
43
44struct atusd_dsc {
45    int fd;
46    void *mem;
47};
48
49
50struct atusd_dsc *atusd_open(void)
51{
52    struct atusd_dsc *dsc;
53
54    dsc = malloc(sizeof(*dsc));
55    if (!dsc) {
56        perror("malloc");
57        exit(1);
58    }
59
60    dsc->fd = open("/dev/mem", O_RDWR);
61    if (dsc->fd < 0) {
62        perror("/dev/mem");
63        exit(1);
64    }
65    dsc->mem = mmap(NULL, PAGE_SIZE*3*16, PROT_READ | PROT_WRITE,
66        MAP_SHARED, dsc->fd, SOC_BASE);
67        if (dsc->mem == MAP_FAILED) {
68                perror("mmap");
69                exit(1);
70        }
71
72    /* set the output levels */
73    PDDATS = nSEL | VDD_OFF;
74    PDDATC = SCLK | SLP_TR;
75
76    /* take the GPIOs away from the MMC controller */
77    PDFUNC = MxSx | SCLK | SLP_TR | IRQ | nSEL;
78    PDFUNS = CLK;
79
80    /* set the pin directions */
81    PDDIRC = IRQ;
82    PDDIRS = MxSx | CLK | SCLK | SLP_TR | nSEL;
83
84    /* enable power */
85    PDDATC = VDD_OFF;
86
87    /* set the MSC clock to 316 MHz / 21 = 16 MHz */
88    MSCCDR = 20;
89    /*
90     * Enable the MSC clock. We need to do this before accessing any
91     * registers of the MSC block !
92     */
93    CLKGR &= ~(1 << 7);
94    /* bus clock = MSC clock / 1 */
95    MSC_CLKRT = 0;
96    /* start MMC clock output */
97    MSC_STRPCL = 2;
98
99    return dsc;
100}
101
102
103void atusd_close(struct atusd_dsc *dsc)
104{
105    /* stop the MMC clock */
106    MSC_STRPCL = 1;
107
108    /* cut the power */
109    PDDATS = VDD_OFF;
110
111    /* make all MMC pins inputs */
112    PDDIRC = MxSx | CLK | SCLK | SLP_TR | IRQ | nSEL;
113}
atusd/tools/try.c
1struct atusd_dsc;
2
3
4int main(void)
5{
6    struct atusd_dsc *dsc;
7    char tmp;
8
9    dsc = atusd_open();
10    read(1, tmp, 1);
11    atusd_close(dsc);
12
13    return 0;
14}

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