COE 305.02 (Term 062)
Name
ID Number
Quiz # 2: Tue 27 March 2007
1. Fill in the spaces (show all your calculations made to get your answers):
a. A TTL circuit has Voutput, high = 3.2 V. When connected to a standard TTL input with Vinput, high, min
= 2 V, the largest noise pickup that can be tolerated is 2 – 3.2 = -1.2 V (indicate polarity).
b. In the 0 logic state, a TTL input can source up to 1.6 mA. The minimum current drive capability of a
buffer having a fan out of 20 such inputs at that logic state is 20 x 1.6 = 32 mA.
c. HOLD, HLDA, RQ/GT is an 8086 pin used in conjunction with control of the busses and direct memory
access (DMA).
d. With a 4 MHz processor clock, every wait state adds 1/(4 MHz) = 250 ns to the duration of the read cycle.
e. #IOWC, #IORC, #MRDC, #MWTC is an example of control signals generated by the 8288 bus controller
2. Give:
a. The part number of one member of the 8086 chip set and mention its function
The 8284A: Clock generator, The 8288: Bus controller
b. An 8086 pin used for communication between the processor and the 8087 coprocessor
#TEST, RQ/GT, QS0,1
c. The 8086 output signal that is used by buffers driving the AD bus to avoid loading the bus while it is
carrying the address output from the processor
#DEN
d. The processor pin used to reboot an 8086-based computer system
RESET
e. One function performed by the 8284A which is related to interfacing memory devices to the 8086
Synchronizes the READY output with the clock before connecting to the processor
3. Indicate whether True or False:
a. #S0,#S1,#S2 are 8086 outputs when the MN/#MX input is tied to ground
True
b. The 8087 has a stack of 128-bit registers used to store floating point operands False
c. The following controls values indicate a memory write cycle: #WR=0, IO/#M= 1 False, it is an I/O write
d. ALE is active high for the full duration of clock cycles T1 and T2 False. It ends during T1.
e. A memory chip with an access time of 350 ns is usable with an 8086 processor running with a 5 MHz
clock without the need for any wait states. True