HPK taruh disini
Microprocessors are generally utilized for relatively high
performance applications where cost and size are not critical selection
criteria. Because microprocessor chips have their entire function
dedicated to the CPU and thus have room for more circuitry to increase
execution speed, they can achieve very high-levels of processing power.
However, microprocessors require external memory and I/O hardware.
Microprocessor chips are used in desktop PCs and workstations where
software compatibility, performance, generality, and flexibility are
important.
By contrast, microcontroller chips are usually designed to minimize the total chip count and cost by incorporating memory and I/O on the chip. They are often "application specialized" at the expense of flexibilit 7 In some cases, the microcontroller has enough resources on-chip that it is the only IC required for a product. Examples of a single-chip application include the key fob used to arm a security system, a toaster, or hand-held games. The hardware interfaces of both devices have much in common, and those of the microcontrollers are generally a simplified subset of the microprocessor. The primary design goals for each type of chip can be summarized this way:
One advantage the Harvard architecture has for embedded applications is due to the two types of memory used in embedded systems. A fixed program and constants can be stored in non-volatile ROM memory while working variable data storage can reside in volatile RAM. Volatile memory loses its contents when power is removed, but non-volatile ROM memory always maintains its contents even after power is removed.
The Harvard architecture also has the potential advantage of a separate interface allowing twice the memory transfer rate by allowing instruction fetches to occur in parallel with data transfers. Unfortunately, in most Harvard architecture machines, the memory is connected to the CPU using a bus that limits the parallelism to a single bus. A typical embedded computer consists of the CPU, memory, and I/O. They are most often connected by means of a shared bus for communication, as shown in Figure 1-2.
By contrast, microcontroller chips are usually designed to minimize the total chip count and cost by incorporating memory and I/O on the chip. They are often "application specialized" at the expense of flexibilit 7 In some cases, the microcontroller has enough resources on-chip that it is the only IC required for a product. Examples of a single-chip application include the key fob used to arm a security system, a toaster, or hand-held games. The hardware interfaces of both devices have much in common, and those of the microcontrollers are generally a simplified subset of the microprocessor. The primary design goals for each type of chip can be summarized this way:
- microprocessors are most flexible
- microcontrollers are most compact
One advantage the Harvard architecture has for embedded applications is due to the two types of memory used in embedded systems. A fixed program and constants can be stored in non-volatile ROM memory while working variable data storage can reside in volatile RAM. Volatile memory loses its contents when power is removed, but non-volatile ROM memory always maintains its contents even after power is removed.
The Harvard architecture also has the potential advantage of a separate interface allowing twice the memory transfer rate by allowing instruction fetches to occur in parallel with data transfers. Unfortunately, in most Harvard architecture machines, the memory is connected to the CPU using a bus that limits the parallelism to a single bus. A typical embedded computer consists of the CPU, memory, and I/O. They are most often connected by means of a shared bus for communication, as shown in Figure 1-2.
