These are used to implement a non- restoring conditional add-subtract division algorithm. The only value of n that satisfies both inequalities is three. Full text of ” analogDevices:: External serial clock frequencies may be as high as the processor’s cycle rate, up to a maximum of Next the shift itself is performed, taking its shift value from the SE register, not from an immediate data value.

See “Powerdown” in Chapter 9, System Interface. Since the loop comparator can only check for one loop termination at a time, falling out of an inner loop by incrementing the PC would go beyond the end address of the outer loop if they terminated on the same instruction. In all cases, however, the program sequencer allows the processor to respond with minimum latency. These status conditions are used with the IF condition clause available on some instructions. With either method, it is important to configure the serial port before enabling it. If an edge-sensitive interrupt request signal occurs when the interrupt is masked, the request is latched but not serviced; the interrupt can then be recognized in software and serviced later.

This allows either the host processor or the ADSPxx to initiate a reset under software control.

case study and overview of adsp 21xx processor

See Chapter 7, “Host Interface Port,” for details. Every device in the ADSP family is a bit, fixed-point machine. The shifter can be divided into the following components: On the next cycle, execution continues at the first instruction of the interrupt service routine.

syudy The same latencies exist for all external interrupts. The single cycle of latency is needed to fetch the instruction stored at the interrupt vector location. In each case, sufficient stack depth is provided to accommodate nesting of all interrupts. When this bit is a 1, multichannel mode is enabled, and some control bits in the SPORTO control register are redefined.


A length value may be associated with each pointer to implement automatic modulo addressing for circular buffers. The output of this stage is then interpolated to 1. Higher and lower precision quotients can also be calculated.

case study and overview of adsp 21xx processor

When a JUMP instruction is decoded, the jump og is input directly to the next address mux of the program sequencer. This allows an input register to provide an operand to the ALU at the beginning of the cycle and be updated with the next operand from memory at the end of the same cycle.

Interrupts can be nested with no additional latency.

case study and overview of adsp 21xx processor

For example, adding two positive numbers must generate a positive result; a change in the sign bit signifies an overflow and sets AV. This delay in turn affects the timing of the serial port transmit interrupt. The count stack may also be popped manually if an early exit from a loop is taken. This delay is different for the transmit and receive interrupts, as explained in the following sections.

Full text of “analogDevices :: ADSP Users Manual 3ed Sep95”

See “Configuration Examples” later in this chapter for examples of frame sync timing. Chapters 5, 6, 7, and 8 describe the additional functional units included in different members of the ADSP family. Assigning a different address location to each one allows the host to control them all. No license Is granted by implication or othenvise under the patent rights of Analog Devices. In some shifter instructions, the shifted output may be logically ORed with the contents of the SR register; the shifter array is bitwise ORed with the current contents of the SR register before being loaded there.


To the processor core, the HIP is a group of eight data-memory-mapped registers. Refer to the Serial Ports chapter for additional information. These bits are both cleared at reset, so that normal framing in both directions is enabled. Because a host computer that requires handshaking must wait for an acknowledgement from the ADSPxx, it is possible to cause such a host to hang. For a write cycle, the host asserts the data. Multifunction instructions combine one or more data moves with a computation.

In that same cycle, processors which have the relevant functional units can also: When IMASK is pushed, it is automatically reloaded with a new value that determines whether or not interrupt nesting is allowed based on the value of the interrupt nesting enable bit in ICNTL. The host asserts HRW and the address.

IMASK is set to zero upon a processor reset. Only one bank is accessible at a time.