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== The DAC ==
== The DAC ==
<a name="DAC_interface" id="DAC_interface"></a>
=== Interface ===
=== Interface ===
The three lines of the interface are ''SYNC'', ''SCLK'', and ''D_in''. A write to the DAC begins with a falling edge of ''SYNC''. The next 19 bits (counted off by ''SCLK'') are saved into a shift register The next transfer begins on another falling edge of ''SYNC'', but transfers do not overlap or interrupt. A minimum of 200ns is required between exchanges. ''SCLK'' is ignored except during the 19 shift cycles. The minimum clock pulse width is 13ns high and 13ns low, yielding a maximum frequency of 77MHz theoretically. In actual fact the maximum clock frequency is 30MHz and the maximum word frequency is 1.2MHz. For further details on timing and protocol, see the AD5535 data sheet supplied by Analog Devices, in particular "Timing Characteristics" (p.5) and "Functional Description (p.12).
The three lines of the interface are ''SYNC'', ''SCLK'', and ''D_in''. A write to the DAC begins with a falling edge of ''SYNC''. The next 19 bits (counted off by ''SCLK'') are saved into a shift register The next transfer begins on another falling edge of ''SYNC'', but transfers do not overlap or interrupt. A minimum of 200ns is required between exchanges. ''SCLK'' is ignored except during the 19 shift cycles. The minimum clock pulse width is 13ns high and 13ns low, yielding a maximum frequency of 77MHz theoretically. In actual fact the maximum clock frequency is 30MHz and the maximum word frequency is 1.2MHz. For further details on timing and protocol, see the AD5535 data sheet supplied by Analog Devices, in particular "Timing Characteristics" (p.5) and "Functional Description (p.12).
<a name="DAC_emulator" id="DAC_emulator"></a>
=== Emulator ===
=== Emulator ===
*** ''Q'': 14-bit output bus
*** ''Q'': 14-bit output bus
<a name="DAC_controller" id="DAC_controller"></a>
=== Controller ===
=== Controller ===
== The temperature sensor ==
== The temperature sensor ==
<a name="Temp_interface" id="Temp_interface"></a>
=== Interface ===
=== Interface ===
A read operation occurs during a 16-cycle pulse of ''CE''. The first transmitted bit will be zero, followed by ten bits of temperature data (MSB first). The remaining five bits are copies of the final data bit. After ''CE'' goes low ''SDO'' goes into a high-Z state. Temperature data is given in degrees Celsius. The format is two's-complement with two decimal places; in essence it is standard two's-complement, then the result must be divide by four after converting to decimal.
A read operation occurs during a 16-cycle pulse of ''CE''. The first transmitted bit will be zero, followed by ten bits of temperature data (MSB first). The remaining five bits are copies of the final data bit. After ''CE'' goes low ''SDO'' goes into a high-Z state. Temperature data is given in degrees Celsius. The format is two's-complement with two decimal places; in essence it is standard two's-complement, then the result must be divide by four after converting to decimal.
<a name="Temp_emulator" id="Temp_emulator"></a>
=== Emulator ===
=== Emulator ===
*** ''Ser'': serial output line
*** ''Ser'': serial output line
<a name="Temp_controller" id="Temp_controller"></a>
=== Controller ===
=== Controller ===