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SPI Protocol
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<span class="px-3 py-1 bg-yellow-600/20 text-yellow-300 text-sm rounded-full">SPI Protocol</span>
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<h1 class="text-4xl font-bold mb-4 bg-gradient-to-r from-yellow-400 to-orange-500 bg-clip-text text-transparent">
SPI Protocol API
</h1>
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SPI master operations with multiple chip select support and automatic pin reservation
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<h2 class="text-2xl font-bold mb-4 text-white">Overview</h2>
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The SPI Protocol API provides full SPI master support with automatic pin reservation and multiple chip select management.
PoKeys devices support 31-33 chip select capable pins depending on the model.
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<h3 class="text-lg font-semibold mb-2 text-yellow-400">Key Features</h3>
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<li>• Full SPI master support</li>
<li>• Multiple chip select pins (31-33 per device)</li>
<li>• Automatic pin reservation (MOSI, CLK)</li>
<li>• Configurable clock speed and mode</li>
<li>• Hardware constraint enforcement</li>
</ul>
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<h3 class="text-lg font-semibold mb-2 text-orange-400">Pin Assignments</h3>
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<li>• <strong>Pin 23 (MOSI)</strong> - Master Out Slave In</li>
<li>• <strong>Pin 24 (MISO)</strong> - Master In Slave Out</li>
<li>• <strong>Pin 25 (CLK)</strong> - Clock signal</li>
<li>• <strong>CS Pins</strong> - Various pins support chip select</li>
</ul>
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</section>
<section class="mb-12">
<h2 class="text-2xl font-bold mb-6 text-white">Automatic Pin Reservation</h2>
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<h3 class="text-red-400 font-semibold mb-3">Important: Hardware Constraints</h3>
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<li>• <strong>Pin 23 (MOSI)</strong> and <strong>Pin 25 (CLK)</strong> are automatically reserved when SPI is enabled</li>
<li>• These pins cannot be used for other functions while SPI is active</li>
<li>• Configuration validation prevents conflicts</li>
<li>• Use <code>is_pin_capability_supported()</code> to check CS pin availability</li>
</ul>
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<h2 class="text-2xl font-bold mb-6 text-white">Basic SPI Operations</h2>
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<h4 class="font-semibold text-yellow-400 mb-2">Example Usage</h4>
<pre class="text-gray-300"><code>use pokeys_lib::*;
fn main() -> Result<()> {`{`}
let mut device = connect_to_device(0)?;
// Initialize SPI (automatically reserves pins 23 and 25)
device.spi_init()?;
// Configure chip select pin
let cs_pin = 10;
device.validate_pin_capability(cs_pin, "SPI_CS")?;
// SPI transaction
let tx_data = vec![0x01, 0x02, 0x03];
let rx_data = device.spi_transfer(cs_pin, &tx_data)?;
println!(\"Received: {`{`}:?{`}`}\", rx_data);
Ok(())
{`}`}</code></pre>
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<h2 class="text-2xl font-bold mb-6 text-white">Device Model Support</h2>
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<th class="text-left py-2 text-yellow-400">Device Model</th>
<th class="text-left py-2 text-orange-400">Total Pins</th>
<th class="text-left py-2 text-green-400">CS Capable Pins</th>
<th class="text-left py-2 text-blue-400">Reserved Pins</th>
</tr>
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<tr class="border-b border-gray-700">
<td class="py-2 font-semibold">PoKeys56U/56E</td>
<td class="py-2">55</td>
<td class="py-2">31</td>
<td class="py-2">23 (MOSI), 25 (CLK)</td>
</tr>
<tr class="border-b border-gray-700">
<td class="py-2 font-semibold">PoKeys57U/57E</td>
<td class="py-2">57</td>
<td class="py-2">33</td>
<td class="py-2">23 (MOSI), 25 (CLK)</td>
</tr>
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</section>
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<h2 class="text-2xl font-bold mb-4 text-white">Best Practices</h2>
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<h3 class="text-lg font-semibold mb-2 text-green-400">Pin Planning</h3>
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<li>• Reserve pins 23 and 25 for SPI before other pin assignments</li>
<li>• Validate CS pin capability before configuration</li>
<li>• Plan peripheral connections based on available CS pins</li>
</ul>
</div>
<div>
<h3 class="text-lg font-semibold mb-2 text-blue-400">Performance</h3>
<ul class="text-gray-300 space-y-1 text-sm">
<li>• Use appropriate clock speeds for your peripherals</li>
<li>• Minimize CS transitions for better performance</li>
<li>• Consider using bulk transfers for large data</li>
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