d09e9c95fd
Now it is ok to have the first clock pulse after reset. The software does not care. At least there must be a clock after rising the reset.
122 lines
3.3 KiB
C++
122 lines
3.3 KiB
C++
/* SIM card for ATMEL
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*
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* (C) 2020 by Andreas Eversberg <jolly@eversberg.eu>
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* All Rights Reserved
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* NOTE: Reset must be an input pin, not the reset of the controller.
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* The clock pulse must be detected during reset.
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*/
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#if defined(__AVR_ATtiny85__)
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#define RST_PIN 2
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#define CLK_PIN 3
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#define DATA_PIN 4
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#else
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#define CLK_PIN 5
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#define RST_PIN 6
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#define DATA_PIN 7
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#endif
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uint8_t card_data[] = {
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/* Example: Service card for AEG OLYMPIA. */
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0xff, 0xf7, 0x5c, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x47, 0x38,
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0x78, 0x28, 0x07, 0x8c, 0xc7, 0x03, 0xfe, 0xfd,
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0xfb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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};
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volatile uint8_t *rst_in, *clk_in, *data_in, *data_out, *data_mode;
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uint8_t rst_bit, clk_bit, data_bit;
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void setup()
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{
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volatile uint8_t *out, *mode;
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uint8_t port;
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rst_bit = digitalPinToBitMask(RST_PIN);
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port = digitalPinToPort(RST_PIN);
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mode = portModeRegister(port);
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out = portOutputRegister(port);
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rst_in = portInputRegister(port);
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*mode &= ~rst_bit; /* input */
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*out |= rst_bit; /* pullup */
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clk_bit = digitalPinToBitMask(CLK_PIN);
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port = digitalPinToPort(CLK_PIN);
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mode = portModeRegister(port);
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out = portOutputRegister(port);
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clk_in = portInputRegister(port);
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*mode &= ~clk_bit; /* input */
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*out |= clk_bit; /* pullup */
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data_bit = digitalPinToBitMask(DATA_PIN);
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port = digitalPinToPort(DATA_PIN);
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data_mode = portModeRegister(port);
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data_out = portOutputRegister(port);
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data_in = portInputRegister(port);
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*data_mode |= data_bit; /* output */
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/* wait for reset */
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while (!(*rst_in & rst_bit));
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}
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uint8_t byte_count;
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uint8_t bit_count;
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void loop()
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{
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reset:
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/* initial reset state */
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byte_count = 0;
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bit_count = 0;
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*data_out |= data_bit; /* high */
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/* now we have reset, so we wait for the first clock pulse */
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while (!(*clk_in & clk_bit));
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while ((*clk_in & clk_bit));
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/* wait for reset to become low, if not already before first clock pulse (AEG phone) */
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while ((*rst_in & rst_bit));
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next_bit:
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/* present bit */
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if ((card_data[byte_count] >> bit_count) & 1)
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*data_out |= data_bit; /* high */
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else
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*data_out &= ~data_bit; /* low */
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if (++bit_count == 8) {
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bit_count = 0;
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if (++byte_count == sizeof(card_data)) {
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goto reset;
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}
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}
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/* wait for clock pulse */
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while (!(*clk_in & clk_bit)) {
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/* reset counter if reset was detected */
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if ((*rst_in & rst_bit)) {
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goto reset;
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}
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}
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while ((*clk_in & clk_bit)) {
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/* reset counter if reset was detected */
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if ((*rst_in & rst_bit)) {
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goto reset;
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}
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}
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goto next_bit;
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}
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