Section 1 ½ Monolithic Microcomputers 585
Table 2 Intel MCS-48 Microcomputers
|
8021 |
8022 |
8035 |
8039 |
8041 |
8048 |
8049 |
8741 |
8748 |
|
|
Number of pins per package |
28 |
40 |
40 |
40 |
40 |
40 |
40 |
40 |
40 |
|
On-chip instruction ROM size (bytes) |
1K |
2K |
.... |
.... |
1K |
1K |
2K |
1K |
1K |
|
Maximum addressable instruction memory (bytes) |
1K |
2K |
4K |
4K |
1K |
4K |
4K |
1K |
4K |
|
On-chip data storage RAM memory (bytes) |
64 |
64 |
64 |
128 |
64 |
64 |
128 |
64 |
64 |
|
Maximum addressable data storage memory (bytes) |
64 |
64 |
320 |
384 |
64 |
320 |
384 |
64 |
320 |
|
I/O bits |
21 |
23 |
27 |
27 |
18 |
27 |
27 |
18 |
27 |
|
Maximum clock frequency (MHz) |
3 |
3 |
3,6 |
6,11 |
6 |
3,6 |
11 |
6 |
3,6 |
Table 3 The TI-9900 Family
|
TMS9900 |
TMS9900-40 |
SBP9900A |
TMS9980/ TMS9981 |
TMS9985 |
TMS9940 |
|
|
Technology |
NMOS |
NMOS |
I2L |
NMOS |
NMOS |
NMOS |
|
Number of pins per package |
64 |
64 |
64 |
40 |
40 |
40 |
|
Clock rate (MHz) |
3.3 |
4 |
3 |
10 |
5 |
1-5 |
|
Clock |
Off chip |
Off chip |
Off chip |
On chip |
On chip |
On chip |
|
Relative throughput |
1 |
1.3 |
0.9 |
0.6 |
0.65-0.8 |
1.2 |
|
Maximum memory size (bytes) |
65K |
65K |
65K |
16K |
65K |
2.2K |
|
On-chip memory |
. . . . . . . . . |
. . . . . . . . . . . |
. . . . . . . . |
. . . . . . . . . |
256 RAM |
2K ERAM 128 RAM |
|
Number of address bus lines |
15 |
15 |
15 |
14 |
16 |
. . . . . . . . . . |
|
Number of data bus lines |
16 |
16 |
16 |
8 |
8 |
. . . . . . . . . . |
|
Addressable I/O bits |
8K |
8K |
8K |
4K |
32K |
32 |
|
Number of interrupt levels |
16 |
16 |
16 |
5 |
5 |
4 |
Monolithic Microcomputer Families
The Intel MCS-48 is a family of microcontrollers. Introduced in 1976, the Intel 8048 contains an 8-bit microprocessor, program ROM, data RAM, and program controllable I/O lines. Table 2 lists the MCS-48 family members as of late 1978. More details can be found in Gregoretti [1978] and Wakerly [1979].
The family evolved as the amount of on-chip ROM/BAM was increased, as off-chip RAM/I/O expansion capability was added, and as transducers were integrated (e.g., the 8-bit A/D converters on the 8022). As in the Texas Instruments TMS series, there is a large number of chips with varying capability. Although the range of variability appears small, the family is supported by the marketplace. Consider a mass-produced product that employs electronic control, such as an automobile. With production in the millions per year, substantial savings can be realized by using the smallest microcontroller chip with enough capacity for the application. In such products a small saving (e.g., 50 cents to $1) might be due to a smaller chip package (e.g., because the application requires a small number of I/O lines leading to a