Typewriter User Manual

9- 4 MC68340 USER’S MANUAL MOTOROLA
Table 9-1. Boundary Scan Control Bits
Name Bit Number Name Bit Number Name Bit Number
tout2.ctl 29 cs0.ctl 66 ab28.ctl 95
irq7.ctl 52 ab.ctl 83 ab29.ctl 97
irq6.ctl 54 berr.ctl 84 ab30.ctl 99
irq5.ctl 56 db.ctl 85 ab31.ctl 101
cs3.ctl 58 ab24.ctl 87 modck.ctl 122
irq3.ctl 60 ab25.ctl 89 ifetch.ctl 125
cs2.ctl 62 ab26.ctl 91 tout1.ctl 130
cs1.ctl 64 ab27.ctl 93
Boundary scan bit definitions are shown in Table 9-2. The first column in Table 9-2 defines
the bit's ordinal position in the boundary scan register. The shift register bit nearest TDO
(i.e., first to be shifted out) is defined as bit 0; the last bit to be shifted out is 131.
The second column references one of the five MC68340 cell types depicted in Figures
9-3–9-7, which describe the cell structure for each type.
The third column lists the pin name for all pin-related bits or defines the name of
bidirectional control register bits. The active level of the control bits (i.e., output driver on)
is defined by the last digit of the cell type listed for each control bit. For example, the
active-high level for irq7.ctl (bit 52) is logic zero since the cell type is IO.Ctl0. The active
level for ab.ctl (bit 83) is logic one, since the cell type is IO.Ctl1. IO.Ctl0 (see Figure 9-6)
differs from IO.Ctl1 (see Figure 9-5) by an inverter in the output enable path.
The fourth column lists the pin type: TS-Output indicates a three-state output pin, I/O
indicates a bidirectional pin, and OD-I/O denotes an open-drain bidirectional pin. An open-
drain output pin has two states: off (high impedance) and logic zero.
The last column indicates the associated boundary scan register control bit for
bidirectional, three-state, and open-drain output pins.
Bidirectional pins include a single scan bit for data (IO.Cell) as depicted in Figure 9-7.
These bits are controlled by one of the two bits shown in Figures 9-5 and 9-6. The value of
the control bit determines whether the bidirectional pin is an input or an output. One or
more bidirectional data bits can be serially connected to a control bit as shown in Figure 9-
8. Note that, when sampling the bidirectional data bits, the bit data can be interpreted only
after examining the IO control bit to determine pin direction.
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc...